Date: Sat, 21 Jan 2017 09:26:58 +0000 From: "D. E" <cipher_nl@hotmail.com> To: Alex Povolotsky <tarkhil@webmail.sub.ru>, "fs@freebsd.org" <fs@freebsd.org> Subject: Re: Poor ZFS performance Message-ID: <DB6PR0801MB1622E364F7E7BBA170ADCE6397700@DB6PR0801MB1622.eurprd08.prod.outlook.com> In-Reply-To: <083391de-d153-e0f6-c453-63d95d3e1f55@webmail.sub.ru> References: <083391de-d153-e0f6-c453-63d95d3e1f55@webmail.sub.ru>
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>I'm writing lots of (tens of millions) relatively small files, hashing=20 >them out in three-level directory, 100 entries per level. >Speed is quite unsatisfying, about 2 millions files per day writing in=20 >20 processes, that is, about one file per second for process. But that is to be expected, isn't it? You have chosen hardware which is *EX= TREMELY* slow for non-contiguous write access. The Seagate Archive HDD is a= n SMR harddrive suitable for archive storage - not a generic PMR harddrive.= So the Seagate Archive HDD is suitable for makings backups and writing hug= e files like 1TB images which you write from A to Z. SMR drives are notorio= usly slow when it comes to non-contiguous writes, such as writing small fil= es. You can read warnings about SMR and the Seagate Archive HDD in particular e= verywhere on the web. Have you missed them? Slightly exaggerated: your SMR-drive is more like a tapestreamer than a rea= l harddrive. It should be used to store enormous files and used for 'cold s= torage'. Read more about the Seagate Archive HDD on its website: http://www.seagate.= com/enterprise-storage/hard-disk-drives/archive-hdd/ To be honest, it is the worst harddrive one can buy today for the purpose o= f regular storage (hot storage). For cold storage, such as backups like tap= estreamers do the drive is decent, but not good by any means. 1,33TB per pl= atter 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. Regards, CiPHER=
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