Date: Tue, 24 Mar 2015 17:05:45 +0000 From: Dale Kline <DKline@safarimontage.com> To: 'Tom Evans' <tevans.uk@googlemail.com>, Shehbaz Jaffer <shehbazjaffer007@gmail.com> Cc: FreeBSD FS <freebsd-fs@freebsd.org>, grarpamp <grarpamp@gmail.com>, "freebsd-hardware@freebsd.org" <freebsd-hardware@freebsd.org> Subject: RE: Zoned Commands ZBC/ZAC, Shingled SMR drives, ZFS Message-ID: <02F3A553C174554DA1D5EC7CEE9BDDD7011BC3E42B@loki.lvc.com> In-Reply-To: <CAFHbX1KLSuES8rJ1Nzho7g8kj-mD_vRAuCyYvdEK9xpz49QBZA@mail.gmail.com> References: <CAD2Ti2_kQhnDL9nvdCT-zMG1bPeLSqTHemn%2B9hueRDLotmsLmw@mail.gmail.com> <CAPLK-i9OSv4ng-6Bwqc%2Byne%2BimDx_veOkwZij=hC1jLrE_ZUJw@mail.gmail.com> <CAFHbX1KLSuES8rJ1Nzho7g8kj-mD_vRAuCyYvdEK9xpz49QBZA@mail.gmail.com>
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READ THE DOCUMENTATION THOROUGHLY on these SMR drives. There are serious = WRITE restrictions on these drives because of the overlapping (shingled) tr= acks. I have read over several times and am still not sure of all of the c= aveats. As Tom states below, they are to be used mainly in "WRITE ONCE, = READ MANY" environments. -----Original Message----- From: owner-freebsd-hardware@freebsd.org [mailto:owner-freebsd-hardware@fre= ebsd.org] On Behalf Of Tom Evans Sent: Tuesday, March 24, 2015 12:39 PM To: Shehbaz Jaffer Cc: FreeBSD FS; grarpamp; freebsd-hardware@freebsd.org Subject: Re: Zoned Commands ZBC/ZAC, Shingled SMR drives, ZFS On Tue, Mar 24, 2015 at 12:47 PM, Shehbaz Jaffer <shehbazjaffer007@gmail.co= m> wrote: > Hi, > > I was wondering what cost advantage do SMR drive provide as compared=20 > to normal CMR drive? > > 8TB SMR drive - $ 260 > 3TB CMR (Conventional Magnetic Recording drive) - $ 105 > Purchase price is not irrelevant, but the key benefits are increased capaci= ty per disk, and reduced power usage per disk and (multiplied by the increa= se in capacity) per TB. In other words, they disks consume less power, you = need fewer of them, maybe allowing you to run fewer servers. Of course, you also need a mainly read only workload. The RAID rebuild test= from the linked review is *scary*. I wouldn't use these in ZFS raidz witho= ut plenty of disaster recovery testing - how long does it take to re-silver= the pool when you lose a disk and what is the performance characteristics = of the pool whilst it is doing so. Cheers Tom _______________________________________________ freebsd-hardware@freebsd.org mailing list http://lists.freebsd.org/mailman/= listinfo/freebsd-hardware To unsubscribe, send any mail to "freebsd-hardware-unsubscribe@freebsd.org"
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