Reoccurring ZFS performance problems [RESOLVED]
Johan Hendriks
joh.hendriks at gmail.com
Tue Mar 18 13:07:34 UTC 2014
Karl Denninger schreef:
> On 3/18/2014 5:26 AM, mikej wrote:
>> On 2014-03-14 19:04, Matthias Gamsjager wrote:
>>> Much better thx :)
>>>
>>> Will this patch be review by some kernel devs and merged?
>>> _______________________________________________
>>> freebsd-fs at freebsd.org mailing list
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>>> To unsubscribe, send any mail to "freebsd-fs-unsubscribe at freebsd.org"
>>
>> I am a little surprised this thread has been so quiet. I have been
>> running with this patch and my desktop is more pleasant when memory
>> demands are great - no more swapping - and wired no longer grows
>> uncontrollable.
>>
>> Is more review coming the silence is deffining.
>>
> It makes an utterly-enormous difference here.
>
> This is what one of my "nasty-busy" servers looks like this morning
> (it's got a very busy blog on it along with other things, and is
> pretty-quiet right now -- but it won't be in a couple of hours)
>
> 1 users Load 0.22 0.25 0.21 Mar 18 05:55
>
> Mem:KB REAL VIRTUAL VN PAGER SWAP
> PAGER
> Tot Share Tot Share Free in out
> in out
> Act 4238440 31700 7953812 53652 2993908 count
> All 16025k 39644 8680436 249960 pages
> Proc: Interrupts
> r p d s w Csw Trp Sys Int Sof Flt ioflt 2083
> total
> 204 7321 1498 6416 665 313 707 207 cow 12 uart0 4
> 428 zfod 20
> uhci0 16
> 0.4%Sys 0.1%Intr 0.6%User 0.0%Nice 99.0%Idle ozfod pcm0 17
> | | | | | | | | | | %ozfod ehci0 uhci
>> daefr uhci1 21
> dtbuf 417 prcfr 455
> uhci3 ehci
> Namei Name-cache Dir-cache 485892 desvn 1197 totfr 16
> twa0 30
> Calls hits % hits % 136934 numvn react 994
> cpu0:timer
> 8063 8009 99 121473 frevn pdwak 42
> mps0 256
> 871 pdpgs 15
> em0:rx 0
> Disks ada0 da0 da1 da2 da3 da4 da5 intrn 20
> em0:tx 0
> KB/t 0.00 20.46 19.92 0.00 0.00 22.06 44.21 17177460 wire
> em0:link
> tps 0 7 7 0 0 7 11 2131860 act 45 em1:rx 0
> MB/s 0.00 0.15 0.15 0.00 0.00 0.15 0.47 2158808 inact 38
> em1:tx 0
> %busy 0 7 7 0 0 0 0 7512 cache
> em1:link
> 2986396 free
> ahci0:ch0
> buf 16
> cpu1:timer
> 23 cpu11:time
> 17 cpu5:timer
> 13 cpu9:timer
> 44 cpu4:timer
> 35 cpu15:time
> 26 cpu6:timer
> 16 cpu14:time
> 28 cpu7:timer
> 23 cpu13:time
> 23 cpu3:timer
> 43 cpu10:time
> 50 cpu2:timer
> 29 cpu12:time
> 40 cpu8:timer
>
>
> Here's the ARC cache....
>
> [karl at NewFS ~]$ zfs-stats -A
>
> ------------------------------------------------------------------------
> ZFS Subsystem Report Tue Mar 18 05:56:42 2014
> ------------------------------------------------------------------------
>
> ARC Summary: (HEALTHY)
> Memory Throttle Count: 0
>
> ARC Misc:
> Deleted: 1.55m
> Recycle Misses: 66.33k
> Mutex Misses: 1.55k
> Evict Skips: 4.14m
>
> ARC Size: 60.01% 13.40 GiB
> Target Size: (Adaptive) 60.01% 13.40 GiB
> Min Size (Hard Limit): 12.50% 2.79 GiB
> Max Size (High Water): 8:1 22.33 GiB
>
> ARC Size Breakdown:
> Recently Used Cache Size: 79.13% 10.60 GiB
> Frequently Used Cache Size: 20.87% 2.80 GiB
>
> ARC Hash Breakdown:
> Elements Max: 1.34m
> Elements Current: 62.76% 840.43k
> Collisions: 7.02m
> Chain Max: 13
> Chains: 247.65k
>
> ------------------------------------------------------------------------
>
> Note the scale-down from the maximum -- this is with:
>
> [karl at NewFS ~]$ sysctl -a|grep percent
> vfs.zfs.arc_freepage_percent_target: 10
>
> My test machine has a lot less memory in it and there the default
> (25%) appears to be a good value.
>
> Before this delta was put on the code this system would have tried to
> grab the entire 22GB to the exclusion of anything else. What I used
> to do is limit it to 16GB via arc_max which was fine in the mornings
> and overnight, but during the day it didn't cut it -- and there was no
> way to change it without a reboot either. This particular machine has
> 24GB of RAM in it and provides services both externally and internally
> (separate interfaces.)
>
> How efficient is the cache?
>
> [karl at NewFS ~]$ zfs-stats -E
>
> ------------------------------------------------------------------------
> ZFS Subsystem Report Tue Mar 18 05:59:01 2014
> ------------------------------------------------------------------------
>
> ARC Efficiency: 81.13m
> Cache Hit Ratio: 97.84% 79.38m
> Cache Miss Ratio: 2.16% 1.75m
> Actual Hit Ratio: 69.81% 56.64m
>
> Data Demand Efficiency: 99.09% 50.37m
> Data Prefetch Efficiency: 28.77% 1.46m
>
> CACHE HITS BY CACHE LIST:
> Anonymously Used: 28.48% 22.61m
> Most Recently Used: 6.81% 5.40m
> Most Frequently Used: 64.54% 51.23m
> Most Recently Used Ghost: 0.03% 24.86k
> Most Frequently Used Ghost: 0.13% 104.39k
>
> CACHE HITS BY DATA TYPE:
> Demand Data: 62.88% 49.91m
> Prefetch Data: 0.53% 419.73k
> Demand Metadata: 8.28% 6.57m
> Prefetch Metadata: 28.31% 22.47m
>
> CACHE MISSES BY DATA TYPE:
> Demand Data: 26.03% 456.20k
> Prefetch Data: 59.29% 1.04m
> Demand Metadata: 9.84% 172.53k
> Prefetch Metadata: 4.84% 84.81k
>
> ------------------------------------------------------------------------
>
>
How do i apply the patch ?
regards
Johan
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