diff --git a/Makefile b/Makefile
index 68fa8afbd1..61a9dd5bd4 100644
--- a/Makefile
+++ b/Makefile
@@ -299,6 +299,7 @@ go-lint: check-git deps $(GOLANGCI_LINT) $(FAILLINT)
 	@# TODO(bwplotka): Add, Printf, DefaultRegisterer, NewGaugeFunc and MustRegister once exception are accepted. Add fmt.{Errorf}=github.com/pkg/errors.{Errorf} once https://github.com/fatih/faillint/issues/10 is addressed.
 	@$(FAILLINT) -paths "errors=github.com/pkg/errors,\
 github.com/prometheus/tsdb=github.com/prometheus/prometheus/tsdb,\
+github.com/prometheus/prometheus/tsdb/errors=github.com/efficientgo/tools/core/pkg/merrors,\
 github.com/prometheus/prometheus/pkg/testutils=github.com/thanos-io/thanos/pkg/testutil,\
 github.com/prometheus/client_golang/prometheus.{DefaultGatherer,DefBuckets,NewUntypedFunc,UntypedFunc},\
 github.com/prometheus/client_golang/prometheus.{NewCounter,NewCounterVec,NewCounterVec,NewGauge,NewGaugeVec,NewGaugeFunc,\
diff --git a/cmd/thanos/rule.go b/cmd/thanos/rule.go
index 1078c49bd4..f35b03c45f 100644
--- a/cmd/thanos/rule.go
+++ b/cmd/thanos/rule.go
@@ -15,6 +15,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/oklog/run"
@@ -29,7 +30,6 @@ import (
 	"github.com/prometheus/prometheus/rules"
 	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/util/strutil"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/extkingpin"
 
 	"github.com/thanos-io/thanos/pkg/alert"
@@ -811,10 +811,11 @@ func reloadRules(logger log.Logger,
 	ruleFiles []string,
 	ruleMgr *thanosrules.Manager,
 	evalInterval time.Duration,
-	metrics *RuleMetrics) error {
+	metrics *RuleMetrics,
+) error {
 	level.Debug(logger).Log("msg", "configured rule files", "files", strings.Join(ruleFiles, ","))
 	var (
-		errs      errutil.MultiError
+		errs      = merrors.New()
 		files     []string
 		seenFiles = make(map[string]struct{})
 	)
diff --git a/cmd/thanos/tools.go b/cmd/thanos/tools.go
index c0c9b04ed8..aec498e1e1 100644
--- a/cmd/thanos/tools.go
+++ b/cmd/thanos/tools.go
@@ -6,12 +6,12 @@ package main
 import (
 	"os"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/oklog/run"
 	"github.com/opentracing/opentracing-go"
 	"github.com/prometheus/client_golang/prometheus"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/extkingpin"
 	"github.com/thanos-io/thanos/pkg/rules"
 )
@@ -35,7 +35,7 @@ func registerCheckRules(app extkingpin.AppClause) {
 }
 
 func checkRulesFiles(logger log.Logger, files *[]string) error {
-	var failed errutil.MultiError
+	failed := merrors.New()
 
 	for _, fn := range *files {
 		level.Info(logger).Log("msg", "checking", "filename", fn)
@@ -51,7 +51,7 @@ func checkRulesFiles(logger log.Logger, files *[]string) error {
 		n, errs := rules.ValidateAndCount(f)
 		if errs.Err() != nil {
 			level.Error(logger).Log("result", "FAILED")
-			for _, e := range errs {
+			for _, e := range errs.Err().Errors() {
 				level.Error(logger).Log("error", e.Error())
 				failed.Add(e)
 			}
diff --git a/go.mod b/go.mod
index e3ce8199d3..c1e93ac48c 100644
--- a/go.mod
+++ b/go.mod
@@ -14,6 +14,7 @@ require (
 	github.com/chromedp/chromedp v0.5.3
 	github.com/cortexproject/cortex v1.7.1-0.20210224085859-66d6fb5b0d42
 	github.com/davecgh/go-spew v1.1.1
+	github.com/efficientgo/tools/core v0.0.0-20210201224146-3d78f4d30648
 	github.com/facette/natsort v0.0.0-20181210072756-2cd4dd1e2dcb
 	github.com/fatih/structtag v1.1.0
 	github.com/felixge/fgprof v0.9.1
diff --git a/go.sum b/go.sum
index f530ac84c6..e0b5b58085 100644
--- a/go.sum
+++ b/go.sum
@@ -304,6 +304,8 @@ github.com/eclipse/paho.mqtt.golang v1.2.0/go.mod h1:H9keYFcgq3Qr5OUJm/JZI/i6U7j
 github.com/edsrzf/mmap-go v0.0.0-20170320065105-0bce6a688712/go.mod h1:YO35OhQPt3KJa3ryjFM5Bs14WD66h8eGKpfaBNrHW5M=
 github.com/edsrzf/mmap-go v1.0.0 h1:CEBF7HpRnUCSJgGUb5h1Gm7e3VkmVDrR8lvWVLtrOFw=
 github.com/edsrzf/mmap-go v1.0.0/go.mod h1:YO35OhQPt3KJa3ryjFM5Bs14WD66h8eGKpfaBNrHW5M=
+github.com/efficientgo/tools/core v0.0.0-20210201224146-3d78f4d30648 h1:zY9fs6qlXtS/YlrijZ+7vTqduJRybPYwJ8Mjo4zWrS8=
+github.com/efficientgo/tools/core v0.0.0-20210201224146-3d78f4d30648/go.mod h1:cFZoHUhKg31xkPnPjhPKFtevnx0Xcg67ptBRxbpaxtk=
 github.com/elastic/go-sysinfo v1.1.1 h1:ZVlaLDyhVkDfjwPGU55CQRCRolNpc7P0BbyhhQZQmMI=
 github.com/elastic/go-sysinfo v1.1.1/go.mod h1:i1ZYdU10oLNfRzq4vq62BEwD2fH8KaWh6eh0ikPT9F0=
 github.com/elastic/go-windows v1.0.0 h1:qLURgZFkkrYyTTkvYpsZIgf83AUsdIHfvlJaqaZ7aSY=
diff --git a/pkg/block/fetcher.go b/pkg/block/fetcher.go
index c0e04dbe8e..8a82e9d4b9 100644
--- a/pkg/block/fetcher.go
+++ b/pkg/block/fetcher.go
@@ -14,6 +14,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/golang/groupcache/singleflight"
@@ -28,7 +29,6 @@ import (
 	"gopkg.in/yaml.v2"
 
 	"github.com/thanos-io/thanos/pkg/block/metadata"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/extprom"
 	"github.com/thanos-io/thanos/pkg/model"
 	"github.com/thanos-io/thanos/pkg/objstore"
@@ -285,7 +285,7 @@ type response struct {
 	metas   map[ulid.ULID]*metadata.Meta
 	partial map[ulid.ULID]error
 	// If metaErr > 0 it means incomplete view, so some metas, failed to be loaded.
-	metaErrs errutil.MultiError
+	metaErrs merrors.NilOrMultiError
 
 	noMetas        float64
 	corruptedMetas float64
@@ -362,7 +362,8 @@ func (f *BaseFetcher) fetchMetadata(ctx context.Context) (interface{}, error) {
 		return nil, errors.Wrap(err, "BaseFetcher: iter bucket")
 	}
 
-	if len(resp.metaErrs) > 0 {
+	if resp.metaErrs.Err() != nil {
+		// Incomplete view is fine, errors are handled by metric, but we stil return success.
 		return resp, nil
 	}
 
@@ -433,7 +434,12 @@ func (f *BaseFetcher) fetch(ctx context.Context, metrics *fetcherMetrics, filter
 		metas[id] = m
 	}
 
-	metrics.synced.WithLabelValues(failedMeta).Set(float64(len(resp.metaErrs)))
+	if errs := resp.metaErrs.Err(); errs != nil {
+		metrics.synced.WithLabelValues(failedMeta).Set(float64(len(errs.Errors())))
+	} else {
+		metrics.synced.WithLabelValues(failedMeta).Set(0)
+	}
+
 	metrics.synced.WithLabelValues(noMeta).Set(resp.noMetas)
 	metrics.synced.WithLabelValues(corruptedMeta).Set(resp.corruptedMetas)
 
@@ -454,8 +460,8 @@ func (f *BaseFetcher) fetch(ctx context.Context, metrics *fetcherMetrics, filter
 	metrics.synced.WithLabelValues(loadedMeta).Set(float64(len(metas)))
 	metrics.submit()
 
-	if len(resp.metaErrs) > 0 {
-		return metas, resp.partial, errors.Wrap(resp.metaErrs.Err(), "incomplete view")
+	if errs := resp.metaErrs.Err(); errs != nil {
+		return metas, resp.partial, errors.Wrap(errs, "incomplete view")
 	}
 
 	level.Info(f.logger).Log("msg", "successfully synchronized block metadata", "duration", time.Since(start).String(), "cached", len(f.cached), "returned", len(metas), "partial", len(resp.partial))
diff --git a/pkg/block/writer.go b/pkg/block/writer.go
index 995d8f72ae..4ec46b5986 100644
--- a/pkg/block/writer.go
+++ b/pkg/block/writer.go
@@ -9,13 +9,13 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/tsdb/chunks"
-	tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
 	"github.com/prometheus/prometheus/tsdb/fileutil"
 	"github.com/prometheus/prometheus/tsdb/index"
 )
@@ -56,6 +56,14 @@ type DiskWriter struct {
 
 const tmpForCreationBlockDirSuffix = ".tmp-for-creation"
 
+func closeAll(closers []io.Closer) error {
+	errs := merrors.New()
+	for _, c := range closers {
+		errs.Add(c.Close())
+	}
+	return errs.Err()
+}
+
 // NewDiskWriter allows to write single TSDB block to disk and returns statistics.
 // Destination block directory has to exists.
 func NewDiskWriter(ctx context.Context, logger log.Logger, bDir string) (_ *DiskWriter, err error) {
@@ -68,7 +76,7 @@ func NewDiskWriter(ctx context.Context, logger log.Logger, bDir string) (_ *Disk
 	}
 	defer func() {
 		if err != nil {
-			err = tsdb_errors.NewMulti(err, tsdb_errors.CloseAll(d.closers)).Err()
+			err = merrors.New(err, closeAll(d.closers)).Err()
 			if err := os.RemoveAll(bTmp); err != nil {
 				level.Error(logger).Log("msg", "removed tmp folder after failed compaction", "err", err.Error())
 			}
@@ -102,7 +110,7 @@ func NewDiskWriter(ctx context.Context, logger log.Logger, bDir string) (_ *Disk
 func (d *DiskWriter) Flush() (_ tsdb.BlockStats, err error) {
 	defer func() {
 		if err != nil {
-			err = tsdb_errors.NewMulti(err, tsdb_errors.CloseAll(d.closers)).Err()
+			err = merrors.New(err, closeAll(d.closers)).Err()
 			if err := os.RemoveAll(d.bTmp); err != nil {
 				level.Error(d.logger).Log("msg", "removed tmp folder failed after block(s) write", "err", err.Error())
 			}
@@ -114,7 +122,7 @@ func (d *DiskWriter) Flush() (_ tsdb.BlockStats, err error) {
 	}
 	defer func() {
 		if df != nil {
-			err = tsdb_errors.NewMulti(err, df.Close()).Err()
+			err = merrors.New(err, df.Close()).Err()
 		}
 	}()
 
@@ -128,7 +136,7 @@ func (d *DiskWriter) Flush() (_ tsdb.BlockStats, err error) {
 	}
 	df = nil
 
-	if err := tsdb_errors.CloseAll(d.closers); err != nil {
+	if err := closeAll(d.closers); err != nil {
 		d.closers = nil
 		return tsdb.BlockStats{}, err
 	}
@@ -180,5 +188,5 @@ func (s *statsGatheringSeriesWriter) WriteChunks(chks ...chunks.Meta) error {
 }
 
 func (s statsGatheringSeriesWriter) Close() error {
-	return tsdb_errors.NewMulti(s.iw.Close(), s.cw.Close()).Err()
+	return merrors.New(s.iw.Close(), s.cw.Close()).Err()
 }
diff --git a/pkg/compact/compact.go b/pkg/compact/compact.go
index a4345319fa..b433467416 100644
--- a/pkg/compact/compact.go
+++ b/pkg/compact/compact.go
@@ -5,6 +5,7 @@ package compact
 
 import (
 	"context"
+	stderrors "errors" //lint:ignore faillint explicitly using stderrors.As
 	"fmt"
 	"io/ioutil"
 	"math"
@@ -14,6 +15,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/oklog/ulid"
@@ -27,7 +29,6 @@ import (
 	"github.com/thanos-io/thanos/pkg/block"
 	"github.com/thanos-io/thanos/pkg/block/metadata"
 	"github.com/thanos-io/thanos/pkg/compact/downsample"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/objstore"
 )
 
@@ -543,17 +544,7 @@ func (e HaltError) Error() string {
 // IsHaltError returns true if the base error is a HaltError.
 // If a multierror is passed, any halt error will return true.
 func IsHaltError(err error) bool {
-	if multiErr, ok := errors.Cause(err).(errutil.NonNilMultiError); ok {
-		for _, err := range multiErr {
-			if _, ok := errors.Cause(err).(HaltError); ok {
-				return true
-			}
-		}
-		return false
-	}
-
-	_, ok := errors.Cause(err).(HaltError)
-	return ok
+	return stderrors.As(err, &HaltError{})
 }
 
 // RetryError is a type wrapper for errors that should trigger warning log and retry whole compaction loop, but aborting
@@ -576,17 +567,19 @@ func (e RetryError) Error() string {
 // IsRetryError returns true if the base error is a RetryError.
 // If a multierror is passed, all errors must be retriable.
 func IsRetryError(err error) bool {
-	if multiErr, ok := errors.Cause(err).(errutil.NonNilMultiError); ok {
-		for _, err := range multiErr {
-			if _, ok := errors.Cause(err).(RetryError); !ok {
+	if !stderrors.As(err, &RetryError{}) {
+		return false
+	}
+	// Check if it's not multi-error with some non-retry errors.
+	errs, ok := merrors.AsMulti(err)
+	if ok {
+		for _, e := range errs.Errors() {
+			if !IsRetryError(e) {
 				return false
 			}
 		}
-		return true
 	}
-
-	_, ok := errors.Cause(err).(RetryError)
-	return ok
+	return true
 }
 
 func (cg *Group) areBlocksOverlapping(include *metadata.Meta, exclude ...*metadata.Meta) error {
@@ -953,12 +946,12 @@ func (c *BucketCompactor) Compact(ctx context.Context) (rerr error) {
 		level.Info(c.logger).Log("msg", "start of compactions")
 
 		// Send all groups found during this pass to the compaction workers.
-		var groupErrs errutil.MultiError
+		errs := merrors.New()
 	groupLoop:
 		for _, g := range groups {
 			select {
 			case groupErr := <-errChan:
-				groupErrs.Add(groupErr)
+				errs.Add(groupErr)
 				break groupLoop
 			case groupChan <- g:
 			}
@@ -970,12 +963,12 @@ func (c *BucketCompactor) Compact(ctx context.Context) (rerr error) {
 		// while we were waiting for the last batch of groups to run the compaction.
 		close(errChan)
 		for groupErr := range errChan {
-			groupErrs.Add(groupErr)
+			errs.Add(groupErr)
 		}
 
 		workCtxCancel()
-		if len(groupErrs) > 0 {
-			return groupErrs.Err()
+		if err := errs.Err(); err != nil {
+			return err
 		}
 
 		if finishedAllGroups {
diff --git a/pkg/compact/compact_test.go b/pkg/compact/compact_test.go
index 4f8140e7ce..cb798ddc38 100644
--- a/pkg/compact/compact_test.go
+++ b/pkg/compact/compact_test.go
@@ -6,11 +6,10 @@ package compact
 import (
 	"testing"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/tsdb"
-
 	"github.com/thanos-io/thanos/pkg/block/metadata"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/testutil"
 )
 
@@ -32,7 +31,7 @@ func TestHaltMultiError(t *testing.T) {
 	haltErr := halt(errors.New("halt error"))
 	nonHaltErr := errors.New("not a halt error")
 
-	errs := errutil.MultiError{nonHaltErr}
+	errs := merrors.New(nonHaltErr)
 	testutil.Assert(t, !IsHaltError(errs.Err()), "should not be a halt error")
 
 	errs.Add(haltErr)
@@ -45,15 +44,14 @@ func TestRetryMultiError(t *testing.T) {
 	retryErr := retry(errors.New("retry error"))
 	nonRetryErr := errors.New("not a retry error")
 
-	errs := errutil.MultiError{nonRetryErr}
+	errs := merrors.New(nonRetryErr)
 	testutil.Assert(t, !IsRetryError(errs.Err()), "should not be a retry error")
 
-	errs = errutil.MultiError{retryErr}
+	errs = merrors.New(retryErr)
 	testutil.Assert(t, IsRetryError(errs.Err()), "if all errors are retriable this should return true")
-
 	testutil.Assert(t, IsRetryError(errors.Wrap(errs.Err(), "wrap")), "retry error with wrap")
 
-	errs = errutil.MultiError{nonRetryErr, retryErr}
+	errs = merrors.New(nonRetryErr, retryErr)
 	testutil.Assert(t, !IsRetryError(errs.Err()), "mixed errors should return false")
 }
 
diff --git a/pkg/compact/downsample/downsample.go b/pkg/compact/downsample/downsample.go
index 8d271b3ee6..c4f79c2943 100644
--- a/pkg/compact/downsample/downsample.go
+++ b/pkg/compact/downsample/downsample.go
@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/oklog/ulid"
 	"github.com/pkg/errors"
@@ -20,7 +21,6 @@ import (
 	"github.com/prometheus/prometheus/tsdb/chunks"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/thanos-io/thanos/pkg/block/metadata"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/runutil"
 )
 
@@ -73,10 +73,7 @@ func Downsample(
 	// Remove blockDir in case of errors.
 	defer func() {
 		if err != nil {
-			var merr errutil.MultiError
-			merr.Add(err)
-			merr.Add(os.RemoveAll(blockDir))
-			err = merr.Err()
+			err = merrors.New(err, os.RemoveAll(blockDir)).Err()
 		}
 	}()
 
diff --git a/pkg/compact/downsample/streamed_block_writer.go b/pkg/compact/downsample/streamed_block_writer.go
index 1872091bfd..161ebfc9c1 100644
--- a/pkg/compact/downsample/streamed_block_writer.go
+++ b/pkg/compact/downsample/streamed_block_writer.go
@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
@@ -19,7 +20,6 @@ import (
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/thanos-io/thanos/pkg/block"
 	"github.com/thanos-io/thanos/pkg/block/metadata"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/runutil"
 )
 
@@ -61,12 +61,11 @@ func NewStreamedBlockWriter(
 	// We should close any opened Closer up to an error.
 	defer func() {
 		if err != nil {
-			var merr errutil.MultiError
-			merr.Add(err)
+			errs := merrors.New(err)
 			for _, cl := range closers {
-				merr.Add(cl.Close())
+				errs.Add(cl.Close())
 			}
-			err = merr.Err()
+			err = errs.Err()
 		}
 	}()
 
@@ -143,20 +142,19 @@ func (w *streamedBlockWriter) Close() error {
 	}
 	w.finalized = true
 
-	merr := errutil.MultiError{}
-
+	errs := merrors.New()
 	if w.ignoreFinalize {
 		// Close open file descriptors anyway.
 		for _, cl := range w.closers {
-			merr.Add(cl.Close())
+			errs.Add(cl.Close())
 		}
-		return merr.Err()
+		return errs.Err()
 	}
 
 	// Finalize saves prepared index and metadata to corresponding files.
 
 	for _, cl := range w.closers {
-		merr.Add(cl.Close())
+		errs.Add(cl.Close())
 	}
 
 	if err := w.writeMetaFile(); err != nil {
@@ -167,7 +165,7 @@ func (w *streamedBlockWriter) Close() error {
 		return errors.Wrap(err, "sync blockDir")
 	}
 
-	if err := merr.Err(); err != nil {
+	if err := errs.Err(); err != nil {
 		return errors.Wrap(err, "finalize")
 	}
 
diff --git a/pkg/compactv2/compactor.go b/pkg/compactv2/compactor.go
index 3da860a998..19f5c73605 100644
--- a/pkg/compactv2/compactor.go
+++ b/pkg/compactv2/compactor.go
@@ -9,13 +9,13 @@ import (
 	"io"
 	"strings"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/tsdb/chunkenc"
-	tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
 	"github.com/prometheus/prometheus/tsdb/index"
 	"github.com/thanos-io/thanos/pkg/block"
 )
@@ -83,9 +83,9 @@ func (w *Compactor) WriteSeries(ctx context.Context, readers []block.Reader, sWr
 		closers  []io.Closer
 	)
 	defer func() {
-		errs := tsdb_errors.NewMulti(err)
-		if cerr := tsdb_errors.CloseAll(closers); cerr != nil {
-			errs.Add(errors.Wrap(cerr, "close"))
+		errs := merrors.New()
+		for _, c := range closers {
+			errs.Add(c.Close())
 		}
 		err = errs.Err()
 	}()
diff --git a/pkg/discovery/dns/provider.go b/pkg/discovery/dns/provider.go
index 060d54c57d..923df61a6b 100644
--- a/pkg/discovery/dns/provider.go
+++ b/pkg/discovery/dns/provider.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/prometheus/client_golang/prometheus"
@@ -16,7 +17,6 @@ import (
 
 	"github.com/thanos-io/thanos/pkg/discovery/dns/godns"
 	"github.com/thanos-io/thanos/pkg/discovery/dns/miekgdns"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/extprom"
 )
 
@@ -112,7 +112,7 @@ func GetQTypeName(addr string) (qtype string, name string) {
 // For non-SRV records, it will return an error if a port is not supplied.
 func (p *Provider) Resolve(ctx context.Context, addrs []string) error {
 	resolvedAddrs := map[string][]string{}
-	errs := errutil.MultiError{}
+	errs := merrors.New()
 
 	for _, addr := range addrs {
 		var resolved []string
diff --git a/pkg/errutil/multierror.go b/pkg/errutil/multierror.go
deleted file mode 100644
index aa53706dde..0000000000
--- a/pkg/errutil/multierror.go
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright (c) The Thanos Authors.
-// Licensed under the Apache License 2.0.
-
-package errutil
-
-import (
-	"bytes"
-	"fmt"
-)
-
-// The MultiError type implements the error interface, and contains the
-// Errors used to construct it.
-type MultiError []error
-
-// Add adds the error to the error list if it is not nil.
-func (es *MultiError) Add(err error) {
-	if err == nil {
-		return
-	}
-	if merr, ok := err.(NonNilMultiError); ok {
-		*es = append(*es, merr...)
-	} else {
-		*es = append(*es, err)
-	}
-}
-
-// Err returns the error list as an error or nil if it is empty.
-func (es MultiError) Err() error {
-	if len(es) == 0 {
-		return nil
-	}
-	return NonNilMultiError(es)
-}
-
-type NonNilMultiError MultiError
-
-// Returns a concatenated string of the contained errors.
-func (es NonNilMultiError) Error() string {
-	var buf bytes.Buffer
-
-	if len(es) > 1 {
-		fmt.Fprintf(&buf, "%d errors: ", len(es))
-	}
-
-	for i, err := range es {
-		if i != 0 {
-			buf.WriteString("; ")
-		}
-		buf.WriteString(err.Error())
-	}
-
-	return buf.String()
-}
diff --git a/pkg/receive/handler.go b/pkg/receive/handler.go
index 0337fe495f..425f87ef54 100644
--- a/pkg/receive/handler.go
+++ b/pkg/receive/handler.go
@@ -16,6 +16,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/gogo/protobuf/proto"
@@ -33,7 +34,6 @@ import (
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 
-	"github.com/thanos-io/thanos/pkg/errutil"
 	extpromhttp "github.com/thanos-io/thanos/pkg/extprom/http"
 	"github.com/thanos-io/thanos/pkg/runutil"
 	"github.com/thanos-io/thanos/pkg/server/http/middleware"
@@ -333,7 +333,7 @@ func (h *Handler) receiveHTTP(w http.ResponseWriter, r *http.Request) {
 	case errBadReplica:
 		http.Error(w, err.Error(), http.StatusBadRequest)
 	default:
-		level.Error(h.logger).Log("err", err, "msg", "internal server error")
+		level.Error(h.logger).Log("err", err, "msg", "internal server error while handling receive request")
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 	}
 }
@@ -394,7 +394,7 @@ func (h *Handler) writeQuorum() int {
 // fanoutForward fans out concurrently given set of write requests. It returns status immediately when quorum of
 // requests succeeds or fails or if context is canceled.
 func (h *Handler) fanoutForward(pctx context.Context, tenant string, replicas map[string]replica, wreqs map[string]*prompb.WriteRequest, successThreshold int) error {
-	var errs errutil.MultiError
+	errs := merrors.New()
 
 	fctx, cancel := context.WithTimeout(tracing.CopyTraceContext(context.Background(), pctx), h.options.ForwardTimeout)
 	defer func() {
@@ -691,11 +691,12 @@ func determineWriteErrorCause(err error, threshold int) error {
 		return nil
 	}
 
-	unwrappedErr := errors.Cause(err)
-	errs, ok := unwrappedErr.(errutil.NonNilMultiError)
-	if !ok {
-		errs = []error{unwrappedErr}
+	errs := []error{err}
+	merrs, ok := merrors.AsMulti(err)
+	if ok {
+		errs = merrs.Errors()
 	}
+
 	if len(errs) == 0 {
 		return nil
 	}
@@ -717,12 +718,12 @@ func determineWriteErrorCause(err error, threshold int) error {
 			}
 		}
 	}
-	// Determine which error occurred most.
+
+	// Determine which error occurred the most.
 	sort.Sort(sort.Reverse(expErrs))
 	if exp := expErrs[0]; exp.count >= threshold {
 		return exp.err
 	}
-
 	return err
 }
 
diff --git a/pkg/receive/handler_test.go b/pkg/receive/handler_test.go
index 70637d49fd..b3170f6348 100644
--- a/pkg/receive/handler_test.go
+++ b/pkg/receive/handler_test.go
@@ -10,10 +10,13 @@ import (
 	"math/rand"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"sync"
 	"testing"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
+
 	"github.com/go-kit/kit/log"
 	"github.com/gogo/protobuf/proto"
 	"github.com/golang/snappy"
@@ -25,7 +28,6 @@ import (
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
 	"github.com/thanos-io/thanos/pkg/store/storepb"
 	"github.com/thanos-io/thanos/pkg/store/storepb/prompb"
@@ -42,10 +44,6 @@ func TestDetermineWriteErrorCause(t *testing.T) {
 		{
 			name: "nil",
 		},
-		{
-			name: "nil multierror",
-			err:  errutil.NonNilMultiError([]error{}),
-		},
 		{
 			name:      "matching simple",
 			err:       errConflict,
@@ -54,81 +52,81 @@ func TestDetermineWriteErrorCause(t *testing.T) {
 		},
 		{
 			name: "non-matching multierror",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				errors.New("foo"),
 				errors.New("bar"),
-			}),
+			).Err(),
 			exp: errors.New("2 errors: foo; bar"),
 		},
 		{
 			name: "nested non-matching multierror",
-			err: errors.Wrap(errutil.NonNilMultiError([]error{
+			err: errors.Wrap(merrors.New(
 				errors.New("foo"),
 				errors.New("bar"),
-			}), "baz"),
+			).Err(), "baz"),
 			threshold: 1,
 			exp:       errors.New("baz: 2 errors: foo; bar"),
 		},
 		{
 			name: "deep nested non-matching multierror",
-			err: errors.Wrap(errutil.NonNilMultiError([]error{
+			err: errors.Wrap(merrors.New(
 				errors.New("foo"),
-				errutil.NonNilMultiError([]error{
+				merrors.New(
 					errors.New("bar"),
 					errors.New("qux"),
-				}),
-			}), "baz"),
+				).Err(),
+			).Err(), "baz"),
 			threshold: 1,
-			exp:       errors.New("baz: 2 errors: foo; 2 errors: bar; qux"),
+			exp:       errors.New("baz: 3 errors: foo; bar; qux"),
 		},
 		{
 			name: "matching multierror",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				storage.ErrOutOfOrderSample,
 				errors.New("foo"),
 				errors.New("bar"),
-			}),
+			).Err(),
 			threshold: 1,
 			exp:       errConflict,
 		},
 		{
 			name: "matching but below threshold multierror",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				storage.ErrOutOfOrderSample,
 				errors.New("foo"),
 				errors.New("bar"),
-			}),
+			).Err(),
 			threshold: 2,
 			exp:       errors.New("3 errors: out of order sample; foo; bar"),
 		},
 		{
 			name: "matching multierror many",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				storage.ErrOutOfOrderSample,
 				errConflict,
 				status.Error(codes.AlreadyExists, "conflict"),
 				errors.New("foo"),
 				errors.New("bar"),
-			}),
+			).Err(),
 			threshold: 1,
 			exp:       errConflict,
 		},
 		{
 			name: "matching multierror many, one above threshold",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				storage.ErrOutOfOrderSample,
 				errConflict,
 				tsdb.ErrNotReady,
 				tsdb.ErrNotReady,
 				tsdb.ErrNotReady,
 				errors.New("foo"),
-			}),
+			).Err(),
 			threshold: 2,
 			exp:       errNotReady,
 		},
 		{
 			name: "matching multierror many, both above threshold, conflict have precedence",
-			err: errutil.NonNilMultiError([]error{
+			err: merrors.New(
 				storage.ErrOutOfOrderSample,
 				errConflict,
 				tsdb.ErrNotReady,
@@ -136,73 +134,74 @@ func TestDetermineWriteErrorCause(t *testing.T) {
 				tsdb.ErrNotReady,
 				status.Error(codes.AlreadyExists, "conflict"),
 				errors.New("foo"),
-			}),
+			).Err(),
 			threshold: 2,
 			exp:       errConflict,
 		},
 		{
 			name: "nested matching multierror",
-			err: errors.Wrap(errors.Wrap(errutil.NonNilMultiError([]error{
+			err: errors.Wrap(errors.Wrap(merrors.New(
 				storage.ErrOutOfOrderSample,
 				errors.New("foo"),
 				errors.New("bar"),
-			}), "baz"), "qux"),
+			).Err(), "baz"), "qux"),
 			threshold: 1,
 			exp:       errConflict,
 		},
 		{
 			name: "deep nested matching multierror",
-			err: errors.Wrap(errutil.NonNilMultiError([]error{
-				errutil.NonNilMultiError([]error{
+			err: errors.Wrap(merrors.New(
+				merrors.New(
 					errors.New("qux"),
 					status.Error(codes.AlreadyExists, "conflict"),
 					status.Error(codes.AlreadyExists, "conflict"),
-				}),
+				).Err(),
 				errors.New("foo"),
 				errors.New("bar"),
-			}), "baz"),
+			).Err(), "baz"),
 			threshold: 1,
-			exp:       errors.New("baz: 3 errors: 3 errors: qux; rpc error: code = AlreadyExists desc = conflict; rpc error: code = AlreadyExists desc = conflict; foo; bar"),
+			exp:       errConflict,
 		},
 	} {
-		err := determineWriteErrorCause(tc.err, tc.threshold)
-		if tc.exp != nil {
-			testutil.NotOk(t, err)
-			testutil.Equals(t, tc.exp.Error(), err.Error())
-			continue
-		}
-		testutil.Ok(t, err)
+		t.Run(tc.name, func(t *testing.T) {
+			err := determineWriteErrorCause(tc.err, tc.threshold)
+			if tc.exp != nil {
+				testutil.NotOk(t, err)
+				testutil.Equals(t, tc.exp.Error(), err.Error())
+				return
+			}
+			testutil.Ok(t, err)
+		})
 	}
 }
 
 func newHandlerHashring(appendables []*fakeAppendable, replicationFactor uint64) ([]*Handler, Hashring) {
-	cfg := []HashringConfig{
-		{
-			Hashring: "test",
-		},
-	}
-	var handlers []*Handler
-	// create a fake peer group where we manually fill the cache with fake addresses pointed to our handlers
-	// This removes the network from the tests and creates a more consistent testing harness.
-	peers := &peerGroup{
-		dialOpts: nil,
-		m:        sync.RWMutex{},
-		cache:    map[string]storepb.WriteableStoreClient{},
-		dialer: func(context.Context, string, ...grpc.DialOption) (*grpc.ClientConn, error) {
-			// dialer should never be called since we are creating fake clients with fake addresses
-			// this protects against some leaking test that may attempt to dial random IP addresses
-			// which may pose a security risk.
-			return nil, errors.New("unexpected dial called in testing")
-		},
-	}
+	var (
+		cfg      = []HashringConfig{{Hashring: "test"}}
+		handlers []*Handler
+		// create a fake peer group where we manually fill the cache with fake addresses pointed to our handlers
+		// This removes the network from the tests and creates a more consistent testing harness.
+		peers = &peerGroup{
+			dialOpts: nil,
+			m:        sync.RWMutex{},
+			cache:    map[string]storepb.WriteableStoreClient{},
+			dialer: func(context.Context, string, ...grpc.DialOption) (*grpc.ClientConn, error) {
+				// dialer should never be called since we are creating fake clients with fake addresses
+				// this protects against some leaking test that may attempt to dial random IP addresses
+				// which may pose a security risk.
+				return nil, errors.New("unexpected dial called in testing")
+			},
+		}
+	)
 
+	logger := log.NewLogfmtLogger(os.Stdout)
 	for i := range appendables {
-		h := NewHandler(nil, &Options{
+		h := NewHandler(logger, &Options{
 			TenantHeader:      DefaultTenantHeader,
 			ReplicaHeader:     DefaultReplicaHeader,
 			ReplicationFactor: replicationFactor,
 			ForwardTimeout:    5 * time.Second,
-			Writer:            NewWriter(log.NewNopLogger(), newFakeTenantAppendable(appendables[i])),
+			Writer:            NewWriter(logger, newFakeTenantAppendable(appendables[i])),
 		})
 		handlers = append(handlers, h)
 		h.peers = peers
@@ -226,24 +225,12 @@ func TestReceiveQuorum(t *testing.T) {
 		Timeseries: []prompb.TimeSeries{
 			{
 				Labels: []labelpb.ZLabel{
-					{
-						Name:  "foo",
-						Value: "bar",
-					},
+					{Name: "foo", Value: "bar"},
 				},
 				Samples: []prompb.Sample{
-					{
-						Value:     1,
-						Timestamp: 1,
-					},
-					{
-						Value:     2,
-						Timestamp: 2,
-					},
-					{
-						Value:     3,
-						Timestamp: 3,
-					},
+					{Value: 1, Timestamp: 1},
+					{Value: 2, Timestamp: 2},
+					{Value: 3, Timestamp: 3},
 				},
 			},
 		},
diff --git a/pkg/receive/multitsdb.go b/pkg/receive/multitsdb.go
index ed297db7c8..70cea73f62 100644
--- a/pkg/receive/multitsdb.go
+++ b/pkg/receive/multitsdb.go
@@ -11,6 +11,7 @@ import (
 	"path/filepath"
 	"sync"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
@@ -20,7 +21,6 @@ import (
 	"github.com/prometheus/prometheus/tsdb"
 	"github.com/thanos-io/thanos/pkg/block/metadata"
 	"github.com/thanos-io/thanos/pkg/component"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/objstore"
 	"github.com/thanos-io/thanos/pkg/shipper"
 	"github.com/thanos-io/thanos/pkg/store"
@@ -144,7 +144,7 @@ func (t *MultiTSDB) Flush() error {
 	defer t.mtx.RUnlock()
 
 	errmtx := &sync.Mutex{}
-	merr := errutil.MultiError{}
+	errs := merrors.New()
 	wg := &sync.WaitGroup{}
 	for id, tenant := range t.tenants {
 		db := tenant.readyStorage().Get()
@@ -158,7 +158,7 @@ func (t *MultiTSDB) Flush() error {
 			head := db.Head()
 			if err := db.CompactHead(tsdb.NewRangeHead(head, head.MinTime(), head.MaxTime()-1)); err != nil {
 				errmtx.Lock()
-				merr.Add(err)
+				errs.Add(err)
 				errmtx.Unlock()
 			}
 			wg.Done()
@@ -166,14 +166,14 @@ func (t *MultiTSDB) Flush() error {
 	}
 
 	wg.Wait()
-	return merr.Err()
+	return errs.Err()
 }
 
 func (t *MultiTSDB) Close() error {
 	t.mtx.Lock()
 	defer t.mtx.Unlock()
 
-	merr := errutil.MultiError{}
+	errs := merrors.New()
 	for id, tenant := range t.tenants {
 		db := tenant.readyStorage().Get()
 		if db == nil {
@@ -181,9 +181,9 @@ func (t *MultiTSDB) Close() error {
 			continue
 		}
 		level.Info(t.logger).Log("msg", "closing TSDB", "tenant", id)
-		merr.Add(db.Close())
+		errs.Add(db.Close())
 	}
-	return merr.Err()
+	return errs.Err()
 }
 
 func (t *MultiTSDB) Sync(ctx context.Context) (int, error) {
@@ -196,7 +196,7 @@ func (t *MultiTSDB) Sync(ctx context.Context) (int, error) {
 
 	var (
 		errmtx   = &sync.Mutex{}
-		merr     = errutil.MultiError{}
+		errs     = merrors.New()
 		wg       = &sync.WaitGroup{}
 		uploaded atomic.Int64
 	)
@@ -212,7 +212,7 @@ func (t *MultiTSDB) Sync(ctx context.Context) (int, error) {
 			up, err := s.Sync(ctx)
 			if err != nil {
 				errmtx.Lock()
-				merr.Add(errors.Wrap(err, "upload"))
+				errs.Add(errors.Wrap(err, "upload"))
 				errmtx.Unlock()
 			}
 			uploaded.Add(int64(up))
@@ -220,7 +220,7 @@ func (t *MultiTSDB) Sync(ctx context.Context) (int, error) {
 		}()
 	}
 	wg.Wait()
-	return int(uploaded.Load()), merr.Err()
+	return int(uploaded.Load()), errs.Err()
 }
 
 func (t *MultiTSDB) RemoveLockFilesIfAny() error {
@@ -232,7 +232,7 @@ func (t *MultiTSDB) RemoveLockFilesIfAny() error {
 		return err
 	}
 
-	merr := errutil.MultiError{}
+	errs := merrors.New()
 	for _, fi := range fis {
 		if !fi.IsDir() {
 			continue
@@ -241,12 +241,12 @@ func (t *MultiTSDB) RemoveLockFilesIfAny() error {
 			if os.IsNotExist(err) {
 				continue
 			}
-			merr.Add(err)
+			errs.Add(err)
 			continue
 		}
 		level.Info(t.logger).Log("msg", "a leftover lockfile found and removed", "tenant", fi.Name())
 	}
-	return merr.Err()
+	return errs.Err()
 }
 
 func (t *MultiTSDB) TSDBStores() map[string]storepb.StoreServer {
diff --git a/pkg/receive/writer.go b/pkg/receive/writer.go
index 8fe1cfe68c..82081e88ae 100644
--- a/pkg/receive/writer.go
+++ b/pkg/receive/writer.go
@@ -7,14 +7,13 @@ import (
 	"context"
 	"sync"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/tsdb"
-
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/store/storepb/prompb"
 )
 
@@ -59,7 +58,7 @@ func (r *Writer) Write(ctx context.Context, tenantID string, wreq *prompb.WriteR
 		return errors.Wrap(err, "get appender")
 	}
 
-	var errs errutil.MultiError
+	errs := merrors.New()
 	for _, t := range wreq.Timeseries {
 		lset := make(labels.Labels, len(t.Labels))
 		for j := range t.Labels {
diff --git a/pkg/rules/manager.go b/pkg/rules/manager.go
index 322c785011..34372f2c4b 100644
--- a/pkg/rules/manager.go
+++ b/pkg/rules/manager.go
@@ -15,6 +15,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/gogo/protobuf/proto"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
@@ -23,7 +24,6 @@ import (
 	"github.com/prometheus/prometheus/rules"
 	"gopkg.in/yaml.v3"
 
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/extprom"
 	"github.com/thanos-io/thanos/pkg/rules/rulespb"
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
@@ -277,9 +277,13 @@ func (g configRuleAdapter) validate() (errs []error) {
 
 // ValidateAndCount validates all rules in the rule groups and return overal number of rules in all groups.
 // TODO(bwplotka): Replace this with upstream implementation after https://github.com/prometheus/prometheus/issues/7128 is fixed.
-func ValidateAndCount(group io.Reader) (numRules int, errs errutil.MultiError) {
-	var rgs configGroups
-	d := yaml.NewDecoder(group)
+func ValidateAndCount(group io.Reader) (numRules int, _ *merrors.NilOrMultiError) {
+	var (
+		errs = merrors.New()
+		rgs  configGroups
+		d    = yaml.NewDecoder(group)
+	)
+
 	d.KnownFields(true)
 	if err := d.Decode(&rgs); err != nil {
 		errs.Add(err)
@@ -309,7 +313,7 @@ type configGroups struct {
 // special field in configGroups.configRuleAdapter struct.
 func (m *Manager) Update(evalInterval time.Duration, files []string) error {
 	var (
-		errs            errutil.MultiError
+		errs            = merrors.New()
 		filesByStrategy = map[storepb.PartialResponseStrategy][]string{}
 		ruleFiles       = map[string]string{}
 	)
@@ -349,7 +353,7 @@ func (m *Manager) Update(evalInterval time.Duration, files []string) error {
 		for s, rg := range groupsByStrategy {
 			b, err := yaml.Marshal(configGroups{Groups: rg})
 			if err != nil {
-				errs = append(errs, errors.Wrapf(err, "%s: failed to marshal rule groups", fn))
+				errs.Add(errors.Wrapf(err, "%s: failed to marshal rule groups", fn))
 				continue
 			}
 
diff --git a/pkg/runutil/runutil.go b/pkg/runutil/runutil.go
index 3f817a62ee..32505972b8 100644
--- a/pkg/runutil/runutil.go
+++ b/pkg/runutil/runutil.go
@@ -56,13 +56,13 @@ import (
 	"os"
 	"time"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
-
-	"github.com/thanos-io/thanos/pkg/errutil"
 )
 
+// TODO(bwplotka): Replace with github.com/efficientgo/tools/core
 // Repeat executes f every interval seconds until stopc is closed or f returns an error.
 // It executes f once right after being called.
 func Repeat(interval time.Duration, stopc <-chan struct{}, f func() error) error {
@@ -137,12 +137,12 @@ func ExhaustCloseWithLogOnErr(logger log.Logger, r io.ReadCloser, format string,
 // CloseWithErrCapture runs function and on error return error by argument including the given error (usually
 // from caller function).
 func CloseWithErrCapture(err *error, closer io.Closer, format string, a ...interface{}) {
-	merr := errutil.MultiError{}
+	errs := merrors.New()
 
-	merr.Add(*err)
-	merr.Add(errors.Wrapf(closer.Close(), format, a...))
+	errs.Add(*err)
+	errs.Add(errors.Wrapf(closer.Close(), format, a...))
 
-	*err = merr.Err()
+	*err = errs.Err()
 }
 
 // ExhaustCloseWithErrCapture closes the io.ReadCloser with error capture but exhausts the reader before.
@@ -152,9 +152,9 @@ func ExhaustCloseWithErrCapture(err *error, r io.ReadCloser, format string, a ..
 	CloseWithErrCapture(err, r, format, a...)
 
 	// Prepend the io.Copy error.
-	merr := errutil.MultiError{}
-	merr.Add(copyErr)
-	merr.Add(*err)
+	errs := merrors.New()
+	errs.Add(copyErr)
+	errs.Add(*err)
 
-	*err = merr.Err()
+	*err = errs.Err()
 }
diff --git a/pkg/store/multitsdb.go b/pkg/store/multitsdb.go
index 902611e658..4c8ae2c164 100644
--- a/pkg/store/multitsdb.go
+++ b/pkg/store/multitsdb.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"sync"
 
+	"github.com/efficientgo/tools/core/pkg/merrors"
 	"github.com/go-kit/kit/log"
 	grpc_opentracing "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing"
 	"github.com/opentracing/opentracing-go"
@@ -21,7 +22,6 @@ import (
 	"google.golang.org/grpc/status"
 
 	"github.com/thanos-io/thanos/pkg/component"
-	"github.com/thanos-io/thanos/pkg/errutil"
 	"github.com/thanos-io/thanos/pkg/runutil"
 	"github.com/thanos-io/thanos/pkg/store/labelpb"
 	"github.com/thanos-io/thanos/pkg/store/storepb"
@@ -168,11 +168,11 @@ func (s *tenantSeriesSetServer) Delegate(closer io.Closer) {
 }
 
 func (s *tenantSeriesSetServer) Close() error {
-	var merr errutil.MultiError
+	errs := merrors.New()
 	for _, c := range s.closers {
-		merr.Add(c.Close())
+		errs.Add(c.Close())
 	}
-	return merr.Err()
+	return errs.Err()
 }
 
 func (s *tenantSeriesSetServer) Next() (ok bool) {