ZFS L2ARC - incorrect size and abnormal system load on r255173
Vitalij Satanivskij
satan at ukr.net
Thu Oct 10 10:01:15 UTC 2013
Hm, another strange thing's on another server -
zfs-stats -L
------------------------------------------------------------------------
ZFS Subsystem Report Thu Oct 10 12:56:54 2013
------------------------------------------------------------------------
L2 ARC Summary: (DEGRADED)
Passed Headroom: 8.34m
Tried Lock Failures: 145.66m
IO In Progress: 9.76m
Low Memory Aborts: 526
Free on Write: 1.70m
Writes While Full: 29.28k
R/W Clashes: 341.30k
Bad Checksums: 865.91k
IO Errors: 44.19k
SPA Mismatch: 32.03m
L2 ARC Size: (Adaptive) 189.28 GiB
Header Size: 4.88% 9.24 GiB
Looks like size have nothing similar with IO errors.
So question is - when error's like Bad Checksums and IO Errors can hapend?
Look's like no hardware problem's.
All ssd atached to onboard intel sata controler (Motherboard is Supermicro X9SRL-F)
Vitalij Satanivskij wrote:
VS> Same situation hapend yesterday again :(
VS>
VS> What's confuse me while trying to understend where I'm wrong
VS>
VS>
VS> Firt some info.
VS>
VS> We have zfs pool "POOL" and one more zfs on it "POOL/zfs"
VS>
VS> POOL - have only primarycache enabled "ALL"
VS> POOL/zfs - have both primay and secondary for "ALL"
VS>
VS> POOL have compression=lz4
VS>
VS> POOL/zfs have none
VS>
VS>
VS> POOL - have around 9TB data
VS>
VS> POOL/zfs - have 1TB
VS>
VS> Secondary cache have configuration -
VS>
VS> cache
VS> gpt/cache0 ONLINE 0 0 0
VS> gpt/cache1 ONLINE 0 0 0
VS> gpt/cache2 ONLINE 0 0 0
VS>
VS> gpt/cache0-2 it's intel sdd SSDSC2BW180A4 180gb
VS>
VS> So full real size for l2 is 540GB (realy 489gb)
VS>
VS> First question - data on l2arc will be compressed on not?
VS>
VS> Second in stats we see
VS>
VS> L2 ARC Size: (Adaptive) 2.08 TiB
VS>
VS> eary it was 1.1 1.4 ...
VS>
VS> So a) how cache can be biger than zfs it self
VS> b) in case it's not compressed (answer for first question) how it an be biger than real ssd size?
VS>
VS>
VS> one more coment if l2 arc size grove above phisical sizes I se next stats
VS>
VS> kstat.zfs.misc.arcstats.l2_cksum_bad: 50907344
VS> kstat.zfs.misc.arcstats.l2_io_error: 4547377
VS>
VS> and growing.
VS>
VS>
VS> System is r255173 with patch from rr255173
VS>
VS>
VS> At last maybe somebody have any ideas what's realy hapend...
VS>
VS>
VS>
VS>
VS>
VS> Vitalij Satanivskij wrote:
VS> VS>
VS> VS> One more question -
VS> VS>
VS> VS> we have two counter -
VS> VS>
VS> VS> kstat.zfs.misc.arcstats.l2_size: 1256609410560
VS> VS> kstat.zfs.misc.arcstats.l2_asize: 1149007667712
VS> VS>
VS> VS> can anybody explain how to understand them i.e. l2_asize - real used space on l2arc an l2_size - uncompressed size,
VS> VS>
VS> VS> or maybe something else ?
VS> VS>
VS> VS>
VS> VS>
VS> VS> Vitalij Satanivskij wrote:
VS> VS> VS>
VS> VS> VS> Data on pool have compressratio around 1.4
VS> VS> VS>
VS> VS> VS> On diferent servers with same data type and load L2 ARC Size: (Adaptive) can be diferent
VS> VS> VS>
VS> VS> VS> for example 1.04 TiB vs 1.45 TiB
VS> VS> VS>
VS> VS> VS> But it's all have same porblem - grow in time.
VS> VS> VS>
VS> VS> VS>
VS> VS> VS> More stange for us -
VS> VS> VS>
VS> VS> VS> ARC: 80G Total, 4412M MFU, 5040M MRU, 76M Anon, 78G Header, 2195M Other
VS> VS> VS>
VS> VS> VS> 78G header size and ubnormal -
VS> VS> VS>
VS> VS> VS> kstat.zfs.misc.arcstats.l2_cksum_bad: 210920592
VS> VS> VS> kstat.zfs.misc.arcstats.l2_io_error: 7362414
VS> VS> VS>
VS> VS> VS> sysctl's growing avery second.
VS> VS> VS>
VS> VS> VS> All part's of server (as hardware part's) in in normal state.
VS> VS> VS>
VS> VS> VS> After reboot no problem's for some period untile cache size grow to some limit.
VS> VS> VS>
VS> VS> VS>
VS> VS> VS>
VS> VS> VS> Mark Felder wrote:
VS> VS> VS> MF> On Mon, Oct 7, 2013, at 13:09, Dmitriy Makarov wrote:
VS> VS> VS> MF> >
VS> VS> VS> MF> > How can L2 ARC Size: (Adaptive) be 1.44 TiB (up) with total physical size
VS> VS> VS> MF> > of L2ARC devices 490GB?
VS> VS> VS> MF> >
VS> VS> VS> MF>
VS> VS> VS> MF> http://svnweb.freebsd.org/base?view=revision&revision=251478
VS> VS> VS> MF>
VS> VS> VS> MF> L2ARC compression perhaps?
VS> VS> VS> MF> _______________________________________________
VS> VS> VS> MF> freebsd-current at freebsd.org mailing list
VS> VS> VS> MF> http://lists.freebsd.org/mailman/listinfo/freebsd-current
VS> VS> VS> MF> To unsubscribe, send any mail to "freebsd-current-unsubscribe at freebsd.org"
VS> VS> VS> _______________________________________________
VS> VS> VS> freebsd-current at freebsd.org mailing list
VS> VS> VS> http://lists.freebsd.org/mailman/listinfo/freebsd-current
VS> VS> VS> To unsubscribe, send any mail to "freebsd-current-unsubscribe at freebsd.org"
VS> VS> _______________________________________________
VS> VS> freebsd-current at freebsd.org mailing list
VS> VS> http://lists.freebsd.org/mailman/listinfo/freebsd-current
VS> VS> To unsubscribe, send any mail to "freebsd-current-unsubscribe at freebsd.org"
VS> _______________________________________________
VS> freebsd-current at freebsd.org mailing list
VS> http://lists.freebsd.org/mailman/listinfo/freebsd-current
VS> To unsubscribe, send any mail to "freebsd-current-unsubscribe at freebsd.org"
More information about the freebsd-current
mailing list