Date: Fri, 8 Jun 2018 17:45:58 +0300 From: Christos Chatzaras <chris@cretaforce.gr> To: Daniel Feenberg <feenberg@nber.org> Cc: FreeBSD <freebsd-questions@freebsd.org> Subject: Re: Toshiba disk low performance Message-ID: <1DBCEF1D-DA0D-4B69-978F-1EAA5F4AE138@cretaforce.gr> In-Reply-To: <alpine.LRH.2.21.1806080956020.4882@sas1.nber.org> References: <DC4343C3-AC15-427E-9653-4C6A7F4E34C4@cretaforce.gr> <20180607171933.6b4babd094f4d056da797cf5@sohara.org> <5D96200B-649B-4851-9FC6-F56F3188326B@cretaforce.gr> <d9a93323-cb2c-d7eb-ed5d-657d162c0614@qeng-ho.org> <18DD35BD-0DA5-4186-9633-F9270744F9AD@cretaforce.gr> <alpine.LRH.2.21.1806080956020.4882@sas1.nber.org>
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I run these benchmark tests in Linux which show slow random writes. I = don't think the issue is related to FreeBSD. > On 8 Jun 2018, at 17:02, Daniel Feenberg <feenberg@nber.org> wrote: >=20 >=20 >=20 > On Fri, 8 Jun 2018, Christos Chatzaras wrote: >=20 >> I did some benchmarks and the problem exist in both Linux and = FreeBSD. >>=20 >> I benchmark a server with Toshiba disks and a server with Seagate = disks. >>=20 >> First I install debian without RAID-1. Then I install iozone. >>=20 >> Tests done with hdparm to test disk bandwidth and iozone to test = random read/writes. >>=20 >> Here are the results: >>=20 >> https://hastebin.com/gayidosaju.pas >>=20 >> As you can see the bandwidth for the Toshiba disks is slower than = Seagate but this doesn't really matter. >>=20 >> The problem is the second test that does random read/writes which = show the Toshiba has 10 times slower random write speed than the = Seagate. >>=20 >> That's why the issue happens mostly during a "mysql import" and not = other server tasks. >=20 > Assuming that Smartdisk doesn't show a problem, don't you think that = for some good or bad reason, the writes to the Seagate are async and = writes to the Toshiba are sync? Perhaps FreeBSD has some rules about the = default that Toshiba triggers in a different way than Seagate? >=20 > Daniel Feenberg > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org"
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