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Date:      Thu, 30 Jan 2014 14:18:51 +0200
From:      Vladimir Sharun <atz@ukr.net>
To:        Current FreeBSD <freebsd-current@freebsd.org>
Subject:   Re[2]: ARC "pressured out", how to control/stabilize ? (reformatted to text/plain)
Message-ID:  <1391083826.948700370.cmzf8475@frv45.ukr.net>
In-Reply-To: <52EA3459.3070300@FreeBSD.org>
References:  <1388839805.123581691.q97ijp8l@frv45.ukr.net> <52C93E4D.1050100@FreeBSD.org> <1389005433.815055146.2dcjke36@frv45.ukr.net> <52CA9963.1050507@FreeBSD.org> <1389676958.516993176.oq4lbgg7@frv45.ukr.net> <52D59E36.9040405@FreeBSD.org> <20140115102837.GA98983@hell.ukr.net> <52D66DB6.7030807@FreeBSD.org> <1390900795.258244476.v35k1338@frv45.ukr.net> <52EA3459.3070300@FreeBSD.org>

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Dear Andriy and FreeBSD community,

L2ARC temporarily turned off by setting secondarycache=none everywhere it was enabled,
so no more leak for one particular day.

Here's the top header:
last pid: 89916;  load averages:  2.49,  2.91,  2.89    up 5+19:21:42  14:09:12
561 processes: 2 running, 559 sleeping
CPU:  5.7% user,  0.0% nice, 14.0% system,  1.0% interrupt, 79.3% idle
Mem: 23G Active, 1017M Inact, 98G Wired, 1294M Cache, 3285M Buf, 1997M Free
ARC: 69G Total, 3498M MFU, 59G MRU, 53M Anon, 1651M Header, 4696M Other
Swap:

Here's the calculated vmstat -z (mean all of the allocations, which exceeds 100*1024^2 printed):
UMA Slabs:      199,915M
VM OBJECT:      207,354M
32:     205,558M
64:     901,122M
128:    215,211M
256:    242,262M
4096:   2316,01M
range_seg_cache:        205,396M
zio_buf_512:    1103,31M
zio_buf_16384:  15697,9M
zio_data_buf_16384:     348,297M
zio_data_buf_24576:     129,352M
zio_data_buf_32768:     104,375M
zio_data_buf_36864:     163,371M
zio_data_buf_53248:     100,496M
zio_data_buf_57344:     105,93M
zio_data_buf_65536:     101,75M
zio_data_buf_73728:     111,938M
zio_data_buf_90112:     104,414M
zio_data_buf_106496:    100,242M
zio_data_buf_131072:    61652,5M
dnode_t:        3203,98M
dmu_buf_impl_t: 797,695M
arc_buf_hdr_t:  1498,76M
arc_buf_t:      105,802M
zfs_znode_cache:        352,61M

zio_data_buf_131072 (61652M) + zio_buf_16384 (15698M) = 77350M
easily exceeds ARC total (70G)


Here's the same calculations from exact the same system where L2 was disabled before reboot:
last pid: 63407;  load averages:  2.35,  2.71,  2.73    up 8+19:42:54  14:17:33
527 processes: 1 running, 526 sleeping
CPU:  4.8% user,  0.0% nice,  6.6% system,  1.1% interrupt, 87.4% idle
Mem: 21G Active, 1460M Inact, 99G Wired, 1748M Cache, 3308M Buf, 952M Free
ARC: 87G Total, 4046M MFU, 76G MRU, 37M Anon, 2026M Header, 4991M Other
Swap:

and the vmstat -z filtered:
UMA Slabs:      208,004M
VM OBJECT:      207,392M
32:     172,831M
64:     752,226M
128:    210,024M
256:    244,204M
4096:   2249,02M
range_seg_cache:        245,711M
zio_buf_512:    1145,25M
zio_buf_16384:  15170,1M
zio_data_buf_16384:     422,766M
zio_data_buf_20480:     120,742M
zio_data_buf_24576:     148,641M
zio_data_buf_28672:     112,848M
zio_data_buf_32768:     117,375M
zio_data_buf_36864:     185,379M
zio_data_buf_45056:     103,168M
zio_data_buf_53248:     105,32M
zio_data_buf_57344:     122,828M
zio_data_buf_65536:     109,25M
zio_data_buf_69632:     100,406M
zio_data_buf_73728:     126,844M
zio_data_buf_77824:     101,086M
zio_data_buf_81920:     100,391M
zio_data_buf_86016:     101,391M
zio_data_buf_90112:     112,836M
zio_data_buf_98304:     100,688M
zio_data_buf_102400:    106,543M
zio_data_buf_106496:    108,875M
zio_data_buf_131072:    63190,5M
dnode_t:        3437,36M
dmu_buf_impl_t: 840,62M
arc_buf_hdr_t:  1870,88M
arc_buf_t:      114,942M
zfs_znode_cache:        353,055M

Everything seems within ARC total range.

We will try patch attached within few days and will come back with the result.

Thank you for your help.

> on 28/01/2014 11:28 Vladimir Sharun said the following:
> > Dear Andriy and FreeBSD community,
> > 
> > After applying this path one of the systems runs fine (disk subsystem load low to moderate 
> > - 10-20% busy sustained),
> > 
> > Then I saw this patch was merged to the HEAD and we apply it to the one of the systems 
> > with moderate to high disk load: 30-60% busy (11.0-CURRENT #7 r261118: Fri Jan 24 17:25:08 EET 2014)
> > 
> > Within 4 days we experiencing the same leak(?) as without patch: 
> > 
> > last pid: 53841;  load averages:  4.47,  4.18,  3.78     up 3+16:37:09  11:24:39
> > 543 processes: 6 running, 537 sleeping
> > CPU:  8.7% user,  0.0% nice, 14.6% system,  1.4% interrupt, 75.3% idle
> > Mem: 22G Active, 1045M Inact, 98G Wired, 1288M Cache, 3284M Buf, 2246M Free
> > ARC: 73G Total, 3763M MFU, 62G MRU, 56M Anon, 1887M Header, 4969M Other
> > Swap:
> > 
> > The ARC is populated within 30mins under load to the max (90Gb) then start decreasing.
> > 
> > The delta between Wiread and ARC total start growing from typical 10-12Gb without L2 enabled
> > to the 25Gb with L2 enabled and counting (4 hours ago was 22Gb delta).
> 
> First,  have you checked that vmstat -z output contains the same anomaly as for
> in your original report?
> 
> If yes, the please try to reproduce the problem with the following debugging patch:
> http://people.freebsd.org/~avg/l2arc-b_tmp_cdata-diag.patch
> Please make sure to compile your kernel (and modules) with INVARIANTS.
> 
> -- 
> Andriy Gapon
> _______________________________________________
> freebsd-current@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-current
> To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"



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