config/example: add flag to ignore missing shards to node config

Add examples of option in `.yaml`, `.json` and `.env` files. Update docs.

Signed-off-by: Andrey Butusov <andrey@nspcc.io>

config/example/node.env

@@ -90,6 +90,7 @@ NEOFS_OBJECT_PUT_POOL_SIZE_REMOTE=100
 # Storage engine section
 NEOFS_STORAGE_SHARD_POOL_SIZE=15
 NEOFS_STORAGE_SHARD_RO_ERROR_THRESHOLD=100
+NEOFS_STORAGE_IGNORE_MISSING_SHARDS=false
 ## 0 shard
 ### Flag to refill Metabase from BlobStor
 NEOFS_STORAGE_SHARD_0_RESYNC_METABASE=false

config/example/node.json

@@ -120,6 +120,7 @@
   "storage": {
     "shard_pool_size": 15,
     "shard_ro_error_threshold": 100,
+    "ignore_missing_shards": false,
     "shard": {
       "0": {
         "mode": "read-only",

config/example/node.yaml

@@ -109,6 +109,7 @@ storage:
   # note: shard configuration can be omitted for relay node (see `node.relay`)
   shard_pool_size: 15 # size of per-shard worker pools used for PUT operations
   shard_ro_error_threshold: 100 # amount of errors to occur before shard is made read-only (default: 0, ignore errors)
+  ignore_missing_shards: false # do we need to ignore missing shards (default: false, fail on any shard failure)
 
   shard:
     default: # section with the default shard parameters

docs/storage-node-configuration.md

@@ -151,6 +151,7 @@ Local storage engine configuration.
 |----------------------------|-----------------------------------|---------------|------------------------------------------------------------------------------------------------------------------|
 | `shard_pool_size`          | `int`                             | `20`          | Pool size for shard workers. Limits the amount of concurrent `PUT` operations on each shard.                     |
 | `shard_ro_error_threshold` | `int`                             | `0`           | Maximum amount of storage errors to encounter before shard automatically moves to `Degraded` or `ReadOnly` mode. |
+| `ignore_missing_shards`    | `bool`                            | `false`       | Flag that specifies whether missing shards should be ignored.                                                    |
 | `shard`                    | [Shard config](#shard-subsection) |               | Configuration for separate shards.                                                                               |
 
 ## `shard` subsection