Date: Fri, 21 Oct 2016 00:56:33 +0100 From: Steven Hartland <killing@multiplay.co.uk> To: Jonathan Chen <jonc@chen.org.nz> Cc: freebsd-stable@freebsd.org Subject: Re: zfs, a directory that used to hold lot of files and listing pause Message-ID: <1b187ab5-cf67-bf66-ab5f-8ec5ae29c140@multiplay.co.uk> In-Reply-To: <CAJuc1zNDDKX%2BqopGkNw=B5_mQgv5%2Bn9N2Bhh4i=qBWrXXaCtxA@mail.gmail.com> References: <4d9269af-ed64-bb73-eb7f-98a3f5ffd5a2@norma.perm.ru> <nub8aq$203d$1@oper.dinoex.de> <CAJuc1zPJWAQbqQGLJdD_Zm_J8Z1tk_J9Tat7=%2BR90q37Ud54qA@mail.gmail.com> <92607b3b-a2d1-2391-5bd6-9781f426d7a6@multiplay.co.uk> <CAJuc1zNDDKX%2BqopGkNw=B5_mQgv5%2Bn9N2Bhh4i=qBWrXXaCtxA@mail.gmail.com>
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On 20/10/2016 23:48, Jonathan Chen wrote:
> On 21 October 2016 at 11:27, Steven Hartland <killing@multiplay.co.uk> wrote:
>> On 20/10/2016 22:18, Jonathan Chen wrote:
>>> On 21 October 2016 at 09:09, Peter <pmc@citylink.dinoex.sub.org> wrote:
>>> [...]
>>>> I see this on my pgsql_tmp dirs (where Postgres stores intermediate
>>>> query data that gets too big for mem - usually lots of files) - in
>>>> normal operation these dirs are completely empty, but make heavy disk
>>>> activity (even writing!) when doing ls.
>>>> Seems normal, I dont care as long as the thing is stable. One would need
>>>> to check how ZFS stores directories and what kind of fragmentation can
>>>> happen there. Or wait for some future feature that would do
>>>> housekeeping. ;)
>>> I'm seeing this as well with an Odoo ERP running on Postgresql. This
>>> lag does matter to me as this is huge performance hit when running
>>> Postgresql on ZFS, and it would be good to see this resolved.
>>> pg_restores can make the system crawl as well.
>> As mentioned before could you confirm you have disable atime?
> Yup, also set the blocksize to 4K.
>
> 11:46am# zfs get all irontree/postgresql
> NAME PROPERTY VALUE SOURCE
> irontree/postgresql type filesystem -
> irontree/postgresql creation Wed Sep 23 15:07 2015 -
> irontree/postgresql used 43.8G -
> irontree/postgresql available 592G -
> irontree/postgresql referenced 43.8G -
> irontree/postgresql compressratio 1.00x -
> irontree/postgresql mounted yes -
> irontree/postgresql quota none default
> irontree/postgresql reservation none default
> irontree/postgresql recordsize 8K local
> irontree/postgresql mountpoint /postgresql
> inherited from irontree
> irontree/postgresql sharenfs off default
> irontree/postgresql checksum on default
> irontree/postgresql compression off default
> irontree/postgresql atime off local
> irontree/postgresql devices on default
> irontree/postgresql exec on default
> irontree/postgresql setuid on default
> irontree/postgresql readonly off default
> irontree/postgresql jailed off default
> irontree/postgresql snapdir hidden default
> irontree/postgresql aclmode discard default
> irontree/postgresql aclinherit restricted default
> irontree/postgresql canmount on default
> irontree/postgresql xattr off temporary
> irontree/postgresql copies 1 default
> irontree/postgresql version 5 -
> irontree/postgresql utf8only off -
> irontree/postgresql normalization none -
> irontree/postgresql casesensitivity sensitive -
> irontree/postgresql vscan off default
> irontree/postgresql nbmand off default
> irontree/postgresql sharesmb off default
> irontree/postgresql refquota none default
> irontree/postgresql refreservation none default
> irontree/postgresql primarycache all default
> irontree/postgresql secondarycache all default
> irontree/postgresql usedbysnapshots 0 -
> irontree/postgresql usedbydataset 43.8G -
> irontree/postgresql usedbychildren 0 -
> irontree/postgresql usedbyrefreservation 0 -
> irontree/postgresql logbias latency default
> irontree/postgresql dedup off default
> irontree/postgresql mlslabel -
> irontree/postgresql sync standard default
> irontree/postgresql refcompressratio 1.00x -
> irontree/postgresql written 43.8G -
> irontree/postgresql logicalused 43.4G -
> irontree/postgresql logicalreferenced 43.4G -
> irontree/postgresql volmode default default
> irontree/postgresql filesystem_limit none default
> irontree/postgresql snapshot_limit none default
> irontree/postgresql filesystem_count none default
> irontree/postgresql snapshot_count none default
> irontree/postgresql redundant_metadata all default
>
When you see the stalling what does gstat -pd and top -SHz show?
Regards
Steve
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