Date: Thu, 7 Apr 2022 07:25:47 -0400
From: mike tancsa <mike@sentex.net>
To: egoitz@ramattack.net
Cc: freebsd-fs@freebsd.org, freebsd-hackers@freebsd.org, Freebsd performance <freebsd-performance@freebsd.org>
Subject: Re: {* 05.00 *}Re: Re: Desperate with 870 QVO and ZFS
Message-ID: <e58a9978-7ee9-0d42-68da-0ed33f4394fa@sentex.net>
In-Reply-To: <609373d106c2244a8a2a3e2ca5e6eb73@ramattack.net>
References: <4e98275152e23141eae40dbe7ba5571f@ramattack.net> <665236B1-8F61-4B0E-BD9B-7B501B8BD617@ultra-secure.de> <0ef282aee34b441f1991334e2edbcaec@ramattack.net> <28e11d7ec0ac5dbea45f9f271fc28f06@ramattack.net> <ca3f86f2-94a1-be94-ad55-7bd1c9bc50ab@grosbein.net> <7aa95cb4bf1fd38b3fce93bc26826042@ramattack.net> <alpine.GSO.2.20.2204061513180.9475@scrappy.simplesystems.org> <d8eec440-aff5-e2c7-35d5-04ac96939213@sentex.net> <609373d106c2244a8a2a3e2ca5e6eb73@ramattack.net>
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On 4/7/2022 4:59 AM, egoitz@ramattack.net wrote: > > Hi Mike! > > Thanks a lot for your comment. I see. As said before, we didn't really > enable compression because we just keep the config as FreeBSD leaves > by default. Apart from that, having tons of disk space and well... for > avoiding the load of compress/decompress... The main reason was it was > not enabled by default really and not to have seen a real reason for > it.... was not more than that....I appreciate your comments really :) Hi, With respect to compression, I think there is a sweet spot somewhere, where compression makes things faster if your disk IO is the limiting factor and you have spare CPU capacity. I have a separate 13.x zfs server with ztsd enabled and I get compression rations of 15:1 as it stores a lot of giant JSON txt files. Think of the extreme case where you do something like dd if=/dev/zero of=/tank/junk.bin bs=1m count=10000 as this is a 20G file that takes just a few hundred bytes of write IO on a compressed system. Obviously, as the compress ratio reduces in the real world the benefits become less. Where that diminishing return is, not sure. But something to keep in mind ---Mike
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