Date: Thu, 07 Apr 2022 16:01:04 +0200
From: egoitz@ramattack.net
To: mike tancsa <mike@sentex.net>
Cc: freebsd-fs@freebsd.org, freebsd-hackers@freebsd.org, Freebsd performance <freebsd-performance@freebsd.org>
Subject: Re: {* 05.00 *}Re: Re: Re: Desperate with 870 QVO and ZFS
Message-ID: <1c114208ae8387fc7c4291d1cc66227e@ramattack.net>
In-Reply-To: <e58a9978-7ee9-0d42-68da-0ed33f4394fa@sentex.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> <e58a9978-7ee9-0d42-68da-0ed33f4394fa@sentex.net>
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[-- Attachment #1 --] Hi Mike! Thanks a lot for your answer :) :) and your time :) :) Answering below in blue bold... El 2022-04-07 13:25, mike tancsa escribió: > On 4/7/2022 4:59 AM, egoitz@ramattack.net wrote: > >> > 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. > > ZTSD OR ZTSD-2 AS IN SOME MAIL PREVIOUS STEFAN STATED?. I ASSUME ARE NOT THE SAME... ARE THEY?. > > 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 > > TOTALLY TRUE AND TOTALLY AGREE MIKE!! > CHEERS!! [-- Attachment #2 --] <html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /></head><body style='font-size: 10pt; font-family: Verdana,Geneva,sans-serif'> <p>Hi Mike!</p> <p><br /></p> <p>Thanks a lot for your answer :) :) and your time :) :)</p> <p><br /></p> <p>Answering below in blue bold...</p> <div> </div> <p><br /></p> <p>El 2022-04-07 13:25, mike tancsa escribió:</p> <blockquote type="cite" style="padding: 0 0.4em; border-left: #1010ff 2px solid; margin: 0"><!-- html ignored --><!-- head ignored --><!-- meta ignored --> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"><br /> <span style="white-space: nowrap;">On 4/7/2022 4:59 AM, <a href="mailto:egoitz@ramattack.net">egoitz@ramattack.net</a> wrote:</span> <blockquote type="cite" style="padding: 0 0.4em; border-left: #1010ff 2px solid; margin: 0"><br /><span style="white-space: nowrap;"></span></blockquote> <span style="white-space: nowrap;">Hi,</span><br /> <br /> 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.</div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"> </div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"><strong><span style="color: #0000ff;">ztsd or ztsd-2 as in some mail previous Stefan stated?. I assume are not the same... are they?.</span></strong><br /> <br /> <span style="white-space: nowrap;">Think of the extreme case where you do something like</span><br /> <br /> <span style="white-space: nowrap;">dd if=/dev/zero of=/tank/junk.bin bs=1m count=10000</span></div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"> </div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace">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</div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"> </div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"><strong><span style="color: #0000ff;">Totally true and totally agree Mike!!</span></strong></div> <div class="pre" style="margin: 0; padding: 0; font-family: monospace"> </div> <strong><span style="color: #0000ff;">Cheers!!</span></strong></blockquote> </body></html>
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