Date: Sat, 3 Jan 2009 08:01:00 +1100 From: "David N" <davidn04@gmail.com> To: "Frederique Rijsdijk" <frederique@isafeelin.org> Cc: freebsd-questions@freebsd.org Subject: Re: Using HDD's for ZFS: 'desktop' vs 'raid / enterprise' -edition drives? Message-ID: <4d7dd86f0901021301o10f49edbj1e103ab336ab409c@mail.gmail.com> In-Reply-To: <495E17AD.30707@isafeelin.org> References: <495E17AD.30707@isafeelin.org>
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2009/1/3 Frederique Rijsdijk <frederique@isafeelin.org>: > Hi freebsd-questions, > > For personal use (photo/video storage), I'm looking into creating a huge > single ZFS (raidz) volume that will replace my current collection of > drives used as storage. I'm thinking 4*1TB drives in RAID5(z). > > My question is regarding the flavour of drivers that one can choose > from: Desktop class drives, or the so called RAID/Enterprise class drives. > > The difference between the two being the way such a drive handles the > bad-sector/block handling and remapping. I understand that Desktop class > drives do all this internally, and this is a process that can take up to >> >> 60s (even minutes on some), and during this process the drive is > > unavailable to the controller. The RAID edition drives all appoach this > differently and alot faster, typically before 8 seconds. > > How does ZFS handle this? Should I be looking for the RAID class drives > or can Desktop class drives be used here? > > My worry is of course that such a drive (destkop class) will be marked > defective and thrown out of the raid volume if a remapping of bad > sectors occurs and the drive will be unresponsive to the controller/ZFS > for > 8 seconds. > > Some drives can be configured in this area, but not all, and there's > quite a price difference in the two, the desktop class being up to 50% > cheaper in some cases.. > > Anybody that can shed some light on this? > > > Thanks, > > -- Frederique Hi, Before i knew the difference between the two, i got myself a bunch of "desktop" HDD. From what I've experience, freebsd just drops the drive. (Currently running in a gmirror config). I'm not sure about ZFS, but i would assume it would do the same. All you need to the do reattach the drive and it will sync back up again. I didn't know the reason why it dropped off, but when i checked the SMART, it showed 1 bad sector reallocation. If it happens to a disk with UFS, it crashes and restarts the machine, UFS doesn't like disappearing drives. Regards David N
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