This fixes:
```
systemd[1]: Started VictoriaMetrics time series database.
victoria-metrics[379550]: 2021-08-04T19:33:39.833Z panic VictoriaMetrics/lib/storage/partition.go:954 FATAL: unrecoverable error when merging small parts in the partition "/var/lib/victoriametrics/data/small/2021_08": cannot open source part for merging: cannot open metaindex file in stream mode: cannot open file "/var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin": open /var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin: too many open files
victoria-metrics[379550]: panic: FATAL: unrecoverable error when merging small parts in the partition "/var/lib/victoriametrics/data/small/2021_08": cannot open source part for merging: cannot open metaindex file in stream mode: cannot open file "/var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin": open /var/lib/victoriametrics/data/small/2021_08/1228_1228_20210804184120.712_20210804184121.899_16982E83CD7A763A/metaindex.bin: too many open files
victoria-metrics[379550]: goroutine 629 [running]:
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logMessage(0xbb3ea1, 0x5, 0xc001113800, 0x1e7, 0x4)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:270 +0xc69
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logLevelSkipframes(0x1, 0xbb3ea1, 0x5, 0xbe3f8b, 0x4b, 0xc000bb3f88, 0x2, 0x2)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:138 +0xd1
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.logLevel(...)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:130
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger.Panicf(...)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/logger/logger.go:126
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).smallPartsMerger(0xc0014d7980)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:954 +0x145
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).startMergeWorkers.func1(0xc0014d7980)
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:933 +0x2b
victoria-metrics[379550]: created by github.com/VictoriaMetrics/VictoriaMetrics/lib/storage.(*partition).startMergeWorkers
victoria-metrics[379550]: github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/partition.go:932 +0x6c
systemd[1]: victoriametrics.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
systemd[1]: victoriametrics.service: Failed with result 'exit-code'.
systemd[1]: victoriametrics.service: Consumed 587ms CPU time, received 6.5K IP traffic, sent 1.7K IP traffic.
systemd[1]: victoriametrics.service: Scheduled restart job, restart counter is at 2064.
systemd[1]: Stopped VictoriaMetrics time series database.
systemd[1]: victoriametrics.service: Consumed 587ms CPU time, received 6.5K IP traffic, sent 1.7K IP traffic.
systemd[1]: Starting VictoriaMetrics time series database...
```
(cherry picked from commit fb6fbcb85cd0167c9759b82f16013777327c07e5)
62733b37b4 broke evaluation in all
places `pkgs.mysql` was used. Fix this by changing all occurrences to
`pkgs.mariadb`.
(cherry picked from commit 59e0120aa5c1241d48048afa615e25c65d7e366d)
As the only consequence of isSystemUser is that if the uid is null then
it's allocated below 500, if a user has uid = something below 500 then
we don't require isSystemUser to be set.
Motivation: https://github.com/NixOS/nixpkgs/issues/112647
Although the quotes here aren't necessary, they may be if a user cargo-cults this example with a database name with hyphens (or other "unusual" characters).
The old slapd.conf is deprecated. Replace with slapd.d, and use this
opportunity to write some structured settings.
Incidentally, this fixes the fact that openldap is reported up before
any checks have completed, by using forking mode.
These were broken since 2016:
f0367da7d1
since StartLimitIntervalSec got moved into [Unit] from [Service].
StartLimitBurst has also been moved accordingly, so let's fix that one
too.
NixOS systems have been producing logs such as:
/nix/store/wf98r55aszi1bkmln1lvdbp7znsfr70i-unit-caddy.service/caddy.service:31:
Unknown key name 'StartLimitIntervalSec' in section 'Service', ignoring.
I have also removed some unnecessary duplication in units disabling
rate limiting since setting either interval or burst to zero disables it
(ad16158c10/src/basic/ratelimit.c (L16))