* lib/{httpserver,netutil}: allow to define min and max TLS version of the http server
* lib/httpserver: added descriptions about tls supported versions
* lib/netutil: check minimal tls version, added supported tls versions to error
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This reduces scrape duration for targets returning big responses.
The response body was already read into memory in stream parsing mode before this change,
so this commit shouldn't increase memory usage.
Cache sanitized label names and return them next time.
This reduces the number of allocations and speeds up the SanitizeLabelName()
function for common case when the number of unique label names is smaller than 100k
The following regex patterns are optimized:
- literal string match, e.g. "foo"
- prefix match, e.g. "foo.*" and "foo.+"
- substring match, e.g. ".*foo.*" and ".+foo.+"
- alternate values match, e.g. "foo|bar|baz"
This is OK, since the anchors are implicitly applied to the whole regexp.
This optimization should improve the speed for regexp series filters with explicit $ and ^ anchors.
For example, `{label="^(foo|bar)$"}`
These metrics allow alerting when the number of unique series approach the limit.
For example, the following query alerts when the number of series reaches 90% of the configured limit:
vm_hourly_series_limit_current_series / vm_hourly_series_limit_max_series > 0.9
ioutil.ReadAll is deprecated since Go1.16 - see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics requires at least Go1.18, so it is OK to switch from ioutil.ReadAll to io.ReadAll.
This is a follow-up for 02ca2342ab
The ioutil.ReadDir is deprecated since Go1.16 - see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics requires at least Go1.18, so it is time to switch from io.ReadDir to os.ReadDir
This is a follow-up for 02ca2342ab
The ioutil.{Read|Write}File is deprecated since Go1.16 -
see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics needs at least Go1.18, so it is safe to remove ioutil usage
from source code.
This is a follow-up for 02ca2342ab
* lib/storage: bump max merge concurrency for small parts to 15
The change is based on the feedback from users on github.
Thier examples show, that limit of 8 sometimes become a
bottleneck. Users report that without limit concurrency
can climb up to 15-20 merges at once.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* Update lib/storage/partition.go
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
The 429 status code means that the server is overwhelmed with requests.
The client can retry the request after some wait time.
Implement this strategy for service discovery and scrape requests.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2940
* lib/storage: prevent excessive loops when storage is in RO
Returning nil error when storage is in RO mode results
into excessive loops and function calls which could
result into CPU exhaustion. Returning an err instead
will trigger delays in the for loop and save some resources.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* document the change
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/auth: add tests from NewToken function
* lib/auth: update test, fix problem with type conversion
* lib/auth: update test description
* lib/auth: simplify failure tests
Previously the time series could be put into dateMetricIDCache without
registering in the per-day inverted index if GetOrCreateTSIDByName
finds TSID entry in the global index. This could lead to missing
series in query results.
The issue has been introduced in the commit 55e7afae3a,
which has been included in VictoriaMetrics v1.78.0
- show dates in human-readable format, e.g. 2022-05-07, instead of a numeric value
- limit the maximum length of queries and filters shown in trace messages
Previously SearchMetricNames was returning unmarshaled metric names.
This wasn't great for vmstorage, which should spend additional CPU time
for marshaling the metric names before sending them to vmselect.
While at it, remove possible duplicate metric names, which could occur when
multiple samples for new time series are ingested via concurrent requests.
Also sort the metric names before returning them to the client.
This simplifies debugging of the returned metric names across repeated requests to /api/v1/series
This opens doors for implementing vmselect api server at vmselect level,
so top-level vmselect could query lower-level vmselect nodes in the same way
as it queries vmstorage nodes.
This will create the ability to create highly available querying architecture
when multiple independent VictoriaMetrics clusters with the same data
are located in distinct availability zones. In this case we can use top-level
vmselect instead of Promxy for simultaneous querying of all the clusters
in all the AZs.
querytracer has been added to the following storage.Storage methods:
- RegisterMetricNames
- DeleteMetrics
- SearchTagValueSuffixes
- SearchGraphitePaths
If the previous dial attempt was unsuccessful, then all the new dial attempts are skipped
until the background goroutine determines that the given address can be successfully dialed.
This reduces query latency when some of vmstorage nodes are unavailable and dialing them is slow.
This should help with https://github.com/VictoriaMetrics/VictoriaMetrics/issues/711
This commit is based on ideas from the https://github.com/VictoriaMetrics/VictoriaMetrics/pull/2756
The main differences are:
- The check for healthy/unhealthy storage nodes is moved one level lower from app/vmselect/netstorage to lib/netutil.ConnPool.
This makes possible re-using this feature everywhere lib/netutil.ConnPool is used.
- The check doesn't take into account handshake errors for already established connections.
Handshake errors usually mean improperly configured VictoriaMetrics cluster, so they shouldn't be ignored.
The commit 5fb45173ae takes into account only newly registered series
when applying cardinality limits. This means that the cardinality limit could be exceeded with already registered series.
This commit returns back accounting for already registered series when applying cardinality limits.
Previously the creation of per-day indexes and global indexes
for the newly registered time series was decoupled.
Now global indexes and per-day indexes for the current day are created toghether for new time series.
This should speed up registering new time series a bit.
* lib/httpserver: backport changes from master branch
adds basicAuth
adds authKey check for /metrics and /debug/pprof requests
it should improve security for cluster components
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
vmalert: support `limit` param in groups definition
`limit` param limits number of time series samples produced by a single rule
during execution.
On reaching the limit rule will return an err.
Signed-off-by: lihaowei <haoweili35@gmail.com>
The change updates histogram for registering SD update duration
only SD is considered as `active`. SD is active if at least
one scraper for this SD has started.
This change supposed to reduce metrics cardinality produced
by duration histogram which gets updated even if SD isn't configured.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2671
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Workers count for merges affects the max part size during merges. Such behaviour
protects storage from running out of disk space for scenario when all workers
are merging parts with the max size.
This works very well for most cases. But for systems where high number of CPUs
is allocated for vmstorage components this could significantly impact the max
part size and result in more unmerged parts than expected.
While checking multiple production highly loaded setups it was discovered that
`max_over_time(vm_active_merges{type="storage/big}[1h]}"` rarely exceeds 2,
and `max_over_time(vm_active_merges{type="storage/small}[1h]}"` rarely exceeds 4.
The change in this commit limits the max value for concurrency accordingly.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
- Remove unused js bloatware from /targets page. This strips down binary size by more than 100Kb
- Add /service-discovery page for API compatibility with Prometheus
- Properly load bootstrap.min.css from /prometheus/targets
- Serve static contents for /targets page from app/vminsert instead of app/vmselect, because /targets page is served from there
- Take into account `ca`, `key` and `cert` values when generating string representation of TLSConfig.
Print hashes instead of real values because of security considerations.
- Properly update Config.tlsCertDigets when `key` and `cert` values are set.
This allows properly updating scrape targets after these values are updated in configs.
- Do not re-generate certificate from `key` and `cert` values per each call to getTLSCert,
because these values are immutable.
- Do not set `ca` value from `ca_file` value, so it isn't exposed at `/config` page.
- Generate proper error messages on incorrect `key`, `cert` or `ca` values.
The default size of `indexdb/tagFilters` now can be overridden via
`storage.cacheSizeIndexDBTagFilters` flag.
Please, be careful with changing default size since it may
lead to inefficient work of the vmstorage or OOM exceptions.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2663
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
* promrelabel: add support of `lowercase` and `uppercase` relabeling actions
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2664
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/storage: make golangci-lint happy
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
* lib/promscrape/discovery/kubernetes: properly updates discovered scrape works
previously, added or updated scrapeworks may override previuosly
discovered.
it happens because swosByKey may contain small subset of kubernetes
objects with it's labels.
It happens for objectsUpdated and objectsAdded maps, which include only changed elements
* Properly calculate vm_promscrape_discovery_kubernetes_scrape_works
Co-authored-by: f41gh7 <nik@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This adds the ability to utilize sigv4 signing for all AWS services not
just "aps". When the newly introduced property "service" is not set it
will default to "aps".
Signed-off-by: Boris Petersen <boris.petersen@idealo.de>
This should reduce potential spikes in the number of established connections in the following cases:
- when the connection establishing procedure becomes temporarily slow
- after a temporary spike in the rate of ConnPool.Get() calls
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2552
Previously ScrapeConfig.clone() was improperly copying promauth.Secret fields -
their contents was replaced with `<secret>` value.
This led to inability to use passwords and secrets in `-promscrape.config` file.
The bug has been introduced in v1.77.0 in the commit 67b10896d2
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2551
* {lib/promscrape,app/vmagent}: adds sigv4 support for vmagent remoteWrite
moves aws related code into separate lib from lib/promscrape
it allows to write data from vmagent to the AWS managed prometheus (cortex)
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1287
* Apply suggestions from code review
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/{storage,flagutil} - Add option for snapshot autoremoval
- add prometheus-like duration as command flag
- add option to delete stale snapshots
- update duration.go flag to re-use own code
* wip
* lib/flagutil: re-use Duration.Set() call in NewDuration
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
replaces internStringMap with sync.Map - it greatly reduces lock contention
concurently reload scrape work for api watcher - each object labels added by dedicated CPU
changes can be tested with following script https://gist.github.com/f41gh7/6f8f8d8719786aff1f18a85c23aebf70
Reduce the number of memory allocations in this function. This improves its performance by up to 50%.
This should improve service discovery speed when big number of potential targets with big number of meta-labels
are generated by service discovery.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2270
This reduces the number of allocations and improves the performance for updating dropped targets' map.
This map is exposed at /api/v1/targets as in droppedTargets list.
* lib/promscrape: adds job restart method
it must restart only ScrapeConfig with changed content
this change greatly reduce time, that needed for job restart
and it should decrease possible data loss when config frequently changed at kubernetes based deployments
Apply suggestions from code review
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* wip
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/httpserver: added tlsCipherSuites flag
* lib/httpserver: compare lower case strings
* lib/httpserver: use EqualFold
* lib/httpserver: used flagutil.NewArray, supported only strings cipher suites
* lib/httpserver: updated flag description, added flag to documentation
* Update lib/httpserver/httpserver.go
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This change fixes incorrect marshalling for ScrapeConfig
it affects http endpoint and ScrapeConfig checksum.
With omitempty, custom Marshaller is not called if field is not a pointer.
Previously this issue happened at vmalert
* lib/promscrape: allows to use k8s pod name as clusterMemberNum
it must improve user expirience and simplify clustering scrapers.
it must allow to use vmagent cluster with distroless images
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2359
* Apply suggestions from code review
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
previously, if native block cannot be unmarshaled, wg.Done wasn't called by unmarshal work.
It leads to connection blocking and possible dead-lock at client side
This metric is equivalent to `vm_available_memory_bytes`, but it has better name,
since the metric is related to a process, not VictoriaMetrics itself.
Leave `vm_available_memory_bytes` for backwards compatibility.
This should improve the performance for items sorting inside inmemoryBlock.MarshalUnsortedData
if they have common prefix.
While at it, improve the performance for inmemoryBlock.updateCommonPrefix for sorted items.
This should improve performance for inmemoryBlock.MarshalSortedData during background merge.
This reduces memory usage under production workloads by up to 10%,
while CPU spent on GC remains roughly the same.
The CPU spent on GC can be monitored with go_memstats_gc_cpu_fraction metric
* lib/protoparser: changes ParseStream for native format
uses reader instead of http.Request
updates app/vmagent and app/vmagent method usage
* app/vmctl: add verify-block subcommand
it allows to check exported from VictoriaMetrics data block in native format
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2362
Update app/vmctl/README.md
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* lib/{storage,regexpcache}: replaces regexpCacheMap with LRU cache
It should decrease memory usage for regexp caching
with storing cacheEntry by pointer - golang map should be able to effectivly shrink it's size
original issue with this case - unexpected map grows and storage OOM
Apply suggestions from code review
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
Adds missing metrics for regexp cache and regexpPrefixes cache
* wip
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* fix for issue 2255 - matchTagFilters for positive empty-match filters
* add example to comments
* formatting
* add test for positive empty match
* formatting
The lifetime of storageBlock is much shorter comparing to the lifetime of inmemoryPart,
so sync.Pool usage should reduce overall memory usage and improve performance
because of better locality of reference when marshaling inmemoryBlock to inmemoryPart.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2247
There is no need to sort the underlying data according to sorted items there.
This should reduce cpu usage when registering new time series in `indexdb`.
Thanks to @ahfuzhang for the suggestion at https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2245
* lib/discovery/consul: update services on the watcher's start
Previously, watcher's start was only initing goroutines for discovery
but not waiting for the first iteration to end. It means first Consul
discovery wasn't returning discovered targets until the next iteration.
The change makes the watcher's start blocking until we get first discovery
iteration done and all registries updated.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: remove workarounds for consul SD
Now when consul SD lib properly updates services
on the first start, we don't need workarounds in vmalert.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/discovery/consul: update after review
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Postpone the pre-poulation to the last hour of the current day. This should reduce the number
of useless entries in the next per-day index, which shouldn't be created there,
when the corresponding time series are stopped to be pushed during the current day.
- Make the pre-population more smooth in time by using the hash of MetricID instead of MetricID itself
when calculating the need for for the given MetricID pre-population.
- Sync the logic for pre-population of the next day inverted index with the logic of pre-populating tsid cache
after indexdb rotation. This should improve code maintainability.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/430
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1401
* lib/index: reduce read/write load after indexDB rotation
IndexDB in VM is responsible for storing TSID - ID's used for identifying
time series. The index is stored on disk and used by both ingestion and read path.
IndexDB is stored separately to data parts and is global for all stored data.
It can't be deleted partially as VM deletes data parts. Instead, indexDB is
rotated once in `retention` interval.
The rotation procedure means that `current` indexDB becomes `previous`,
and new freshly created indexDB struct becomes `current`. So in any time,
VM holds indexDB for current and previous retention periods.
When time series is ingested or queried, VM checks if its TSID is present
in `current` indexDB. If it is missing, it checks the `previous` indexDB.
If TSID was found, it gets copied to the `current` indexDB. In this way
`current` indexDB stores only series which were active during the retention
period.
To improve indexDB lookups, VM uses a cache layer called `tsidCache`. Both
write and read path consult `tsidCache` and on miss the relad lookup happens.
When rotation happens, VM resets the `tsidCache`. This is needed for ingestion
path to trigger `current` indexDB re-population. Since index re-population
requires additional resources, every index rotation event may cause some extra
load on CPU and disk. While it may be unnoticeable for most of the cases,
for systems with very high number of unique series each rotation may lead
to performance degradation for some period of time.
This PR makes an attempt to smooth out resource usage after the rotation.
The changes are following:
1. `tsidCache` is no longer reset after the rotation;
2. Instead, each entry in `tsidCache` gains a notion of indexDB to which
they belong;
3. On ingestion path after the rotation we check if requested TSID was
found in `tsidCache`. Then we have 3 branches:
3.1 Fast path. It was found, and belongs to the `current` indexDB. Return TSID.
3.2 Slow path. It wasn't found, so we generate it from scratch,
add to `current` indexDB, add it to `tsidCache`.
3.3 Smooth path. It was found but does not belong to the `current` indexDB.
In this case, we add it to the `current` indexDB with some probability.
The probability is based on time passed since the last rotation with some threshold.
The more time has passed since rotation the higher is chance to re-populate `current` indexDB.
The default re-population interval in this PR is set to `1h`, during which entries from
`previous` index supposed to slowly re-populate `current` index.
The new metric `vm_timeseries_repopulated_total` was added to identify how many TSIDs
were moved from `previous` indexDB to the `current` indexDB. This metric supposed to
grow only during the first `1h` after the last rotation.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1401
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* wip
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* lib/promscrape: support prometheus-like duration in scrape configs
The change allows to specify duration values like `1d`, `1w`
for fields `scrape_interval`, `scrape_timeout`, etc.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/817#issuecomment-1033384766
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/blockcache: make linter happy
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/promscrape: support prometheus-like duration in scrape configs
* add support for extra fields `scrape_align_interval` and `scrape_offset`;
* support Prometheus duration parsing for `__scrape_interval__`
and `__scrape_duration__` labels;
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* wip
* wip
* docs/CHANGELOG.md: document the feature
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* fixes service discovery for kubernetes
now it must take in account all pods that belong to the discovered endpoint and endpointslice
adds simple test for endpoints
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2134
* wip
* docs/CHANGELOG.md: document the change
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This should improve data ingestion speed if time series samples are ingested with interval bigger than 2 minutes.
The actual interval could exceed 2 minutes if the original interval between samples doesn't exceed 2 minutes
in the case of slow inserts. Slow inserts may appear in the following cases:
* Big number of new time series are pushed to VictoriaMetrics, so they couldn't be registered in 2 minutes.
* MetricName->tsid cache reset on indexdb rotation or due to unclean shutdown.
In this case VictoriaMetrics needs to load MetricName->tsid entries for all the incoming series from IndexDB.
IndexDB uses the block cache for increasing lookup performance. If the cache has no the needed block,
then IndexDB reads and unpacks the block from disk. This requires an extra disk read IO and CPU.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1401
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2007
This also should increase performance for periodically executed queries with intervals from 2 minutes to 5 minutes.
See the previous similar commit - 43103be011
It is possible that the timeout can be increased further. Let's collect production numbers for this change
so the timeout could be adjusted further.
Previously limits for new caches were taken from cache stats.
These limits could mismatch the original limits. This could result in failed cache load
if the stored cache has been created with the limits obtained from cache stats.
This metric shows the number of CPU cores available to the process.
This allows creating alerting rules on CPU saturation with the following query:
rate(process_cpu_seconds_total[5m]) / process_cpu_cores_available > 0.9
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2107
* optimized code ,because only the first error,so no need var errors []error
* optimized code ,because only the first error,so no need var errors []error
Co-authored-by: lirenzuo <lirenzuo@shein.com>
Previously bytesutil.Resize() was copying the original byte slice contents to a newly allocated slice.
This wasted CPU cycles and memory bandwidth in some places, where the original slice contents wasn't needed
after slize resizing. Switch such places to bytesutil.ResizeNoCopy().
Rename the original bytesutil.Resize() function to bytesutil.ResizeWithCopy() for the sake of improved readability.
Additionally, allocate new slice with `make()` instead of `append()`. This guarantees that the capacity of the allocated slice
exactly matches the requested size. The `append()` could return a slice with bigger capacity as an optimization for further `append()` calls.
This could result in excess memory usage when the returned byte slice was cached (for instance, in lib/blockcache).
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2007
- Optimize Cache.RemoveBlocksFromPart(), so it doesn't need to iterate over all the cached blocks.
- Cache blocks if there were no cache misses during the last 2 minutes.
This may be the case when new blocks are added simultaneously to the storage and to the cache.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2007
Previously these caches could exceed limits set via `-memory.allowedPercent` and/or `-memory.allowedBytes`,
since limits were set independently per each data part. If the number of data parts was big, then limits could be exceeded,
which could result to out of memory errors.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2007
- Document the bugfix at docs/CHANGELOG.md
- Set __address__ field after copying commonLabels to the resulting map of discovered labels.
This makes sure that the correct __address__ label is used.
This should handle the case when the original job_name has been changed in -promscrape.config ,
while the resulting job label remains the same because it is overriden via relabeling.
* vmagent: add error log for skipped data block when rejected by receiving side
Previously, rejected data blocks were silently dropped - only metrics were update.
From operational perspective, having an additional logging for such cases is preferable.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1911
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmagent: throttle log messages about skipped blocks
The new type of logger was added to logger pacakge.
This new type supposed to control number of logged messages
by time.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/logger: make LogThrottler public, so its methods can be inspected by external packages
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
For example, `{__graphite__=~"foo.(bar|baz)"}` is automatically converted to `{__graphite__=~"foo.{bar,baz}"}` before execution.
This allows using multi-value Grafana template variables such as `{__graphite__=~"foo.($app)"}`.
* Document the ability to specify http or https urls in `-auth.config` at docs/CHANGELOG.md
* Move the ReadFileOrHTTP to lib/fs, so it can be re-used in other places where a file
should be read from the given path. For example, in `-promscrape.config` at `vmagent`.
The vm_cache_size_max_bytes metric can be used for determining caches which reach their capacity via the following query:
vm_cache_size_bytes / vm_cache_size_max_bytes > 0.9
* removes FileSize from backup part key
it should fix download restoration for backups
* Update lib/backup/common/part.go
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
