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Date:      Mon, 06 Sep 2010 16:26:22 +0300
From:      Andriy Gapon <avg@icyb.net.ua>
To:        Steven Hartland <killing@multiplay.co.uk>
Cc:        freebsd-fs@freebsd.org, jhell <jhell@DataIX.net>
Subject:   Re: zfs very poor performance compared to ufs due to lack of cache?
Message-ID:  <4C84EBFE.7030408@icyb.net.ua>
In-Reply-To: <C8FDED84AE204EB3B143C3F8301E58E3@multiplay.co.uk>
References:  <5DB6E7C798E44D33A05673F4B773405E@multiplay.co.uk><AANLkTi=6bta-Obrh2ejLCHENEbhV5stbMsvfek3Ki4ba@mail.gmail.com><4C825D65.3040004@DataIX.net>	<7EA7AD058C0143B2BF2471CC121C1687@multiplay.co.uk> <1F64110BFBD5468B8B26879A9D8C94EF@multiplay.co.uk> <4C84C72A.3020506@icyb.net.ua> <C8FDED84AE204EB3B143C3F8301E58E3@multiplay.co.uk>

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on 06/09/2010 16:23 Steven Hartland said the following:
> ----- Original Message ----- From: "Andriy Gapon" <avg@icyb.net.ua>
>>> No joy, still drops down to arc_min even with those two patches and changing
>>> to vm_paging_needed from the post Artem mentioned:
>>> http://lists.freebsd.org/pipermail/freebsd-hackers/2010-August/032731.html
>>>
>>> So I suspect if I hadn't put in a high arc_min as well it would be back down
>>> at silly low levels.
>>
>> But we don't really know this, do we?
>>
>> I think that it would be useful for you and perhaps for us, if you'd set up
>> monitoring (and graphing) of key memory-related parameters.
>> E.g. at least the following sysctls:
>> kstat.zfs.misc.arcstats.size
>> vm.stats.vm.v_pdwakeups
>> vm.stats.vm.v_cache_count
>> vm.stats.vm.v_inactive_count
>> vm.stats.vm.v_active_count
>> vm.stats.vm.v_wire_count
>> vm.stats.vm.v_free_count
>>
>> This would allow to see dynamics of memory consumption and correlation with
>> pagedaemon events.
> 
> Now monitoring these each minute to an rrd and text file and updated 8-STABLE
> with the following patches:
> http://people.freebsd.org/~mm/patches/zfs/v15/stable-8-v15.patch
> http://people.freebsd.org/~mm/patches/zfs/zfs_metaslab_v2.patch
> http://people.freebsd.org/~mm/patches/zfs/zfs_abe_stat_rrwlock.patch
> and then the needfree.patch I already posted.

Cool!

What about vm_paging_needed() patch?

-- 
Andriy Gapon



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