Date: Sat, 21 Jan 2017 10:53:23 +0100 From: Ben RUBSON <ben.rubson@gmail.com> To: "fs@freebsd.org" <fs@freebsd.org> Subject: Re: Poor ZFS performance Message-ID: <963575CE-F74A-456A-AB33-3C5F6828ED17@gmail.com> In-Reply-To: <e30bf385-8e5e-d274-35f5-778f380b1277@webmail.sub.ru> References: <083391de-d153-e0f6-c453-63d95d3e1f55@webmail.sub.ru> <DB6PR0801MB1622E364F7E7BBA170ADCE6397700@DB6PR0801MB1622.eurprd08.prod.outlook.com> <e30bf385-8e5e-d274-35f5-778f380b1277@webmail.sub.ru>
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Hi, What about a primary pool made of SSD ? They should fit your workload much better than platter disks. Ben > On 21 Jan 2017, at 10:47, Alex Povolotsky <tarkhil@webmail.sub.ru> = wrote: >=20 > So fetching data to, say, ST2000NM0055-1V4104, and than zfs send | zfs = receive to Archive HDD will do the trick? >=20 > Seems like the answer is "yes", I've got 3-4 times speed improvement. = In an hour, I'll try partial transfer. >=20 > What 8 Tb disk would you recommend for raidz? >=20 > On 21.01.2017 12:26, D. E wrote: >>> I'm writing lots of (tens of millions) relatively small files, = hashing >>> them out in three-level directory, 100 entries per level. >>=20 >>> Speed is quite unsatisfying, about 2 millions files per day writing = in >>> 20 processes, that is, about one file per second for process. >>=20 >> But that is to be expected, isn't it? You have chosen hardware which = is *EXTREMELY* slow for non-contiguous write access. The Seagate Archive = HDD is an SMR harddrive suitable for archive storage - not a generic PMR = harddrive. So the Seagate Archive HDD is suitable for makings backups = and writing huge files like 1TB images which you write from A to Z. SMR = drives are notoriously slow when it comes to non-contiguous writes, such = as writing small files. >>=20 >> You can read warnings about SMR and the Seagate Archive HDD in = particular everywhere on the web. Have you missed them? >>=20 >> Slightly exaggerated: your SMR-drive is more like a tapestreamer than = a real harddrive. It should be used to store enormous files and used for = 'cold storage'. >>=20 >> Read more about the Seagate Archive HDD on its website: = http://www.seagate.com/enterprise-storage/hard-disk-drives/archive-hdd/ >>=20 >> To be honest, it is the worst harddrive one can buy today for the = purpose of regular storage (hot storage). For cold storage, such as = backups like tapestreamers do the drive is decent, but not good by any = means. 1,33TB per platter is disappointing for SMR considering the = massive downsides. And some PMR drives are even cheaper per gigabyte = than this SMR drive. So i strongly recommend against SMR at this time. >>=20 >> Regards, >> CiPHER >>=20 > _______________________________________________ > freebsd-fs@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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