Date: Sat, 30 Oct 2010 20:38:04 +0200 From: =?iso-8859-1?Q?Peter_Ankerst=E5l?= <peter@pean.org> To: Sean <sean@ttys0.net> Cc: freebsd-fs@freebsd.org Subject: Re: Raid + zfs performace. Message-ID: <FCABED3C-A1BC-4B72-9289-C16BAD4F6B39@pean.org> In-Reply-To: <AANLkTima02fBo8gRwCTZH3xWV1mM3r439tgQCXVa4RwB@mail.gmail.com> References: <D2954020-C3A0-46EC-8C64-EB57EA1E9B21@pean.org> <AANLkTinQWchAPtcqcO3mDt9gKK5tCsHo8khyiD69M4BV@mail.gmail.com> <86693036-9351-4303-BADA-C99F7A4C375C@pean.org> <AANLkTima02fBo8gRwCTZH3xWV1mM3r439tgQCXVa4RwB@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 30 okt 2010, at 20.09, Sean wrote: >> I thought maybe because the existing pool is kind of r/w saturated >> it should be better to create a new independent pool for the new >> drives. In that way the heavy activity would not "spread" to the >> new drives. >=20 > You're trying to be smarter than ZFS. It's a common syndrome, usually > brought about from years of experience dealing with "dumb" > filesystems. If you create a new independent pool, then you are > guaranteeing that your current r/w saturated pool will stay that way, > unless you manually migrate data off of that pool. If you add storage > to that pool, then you are providing that pool additional resource > that ZFS can then manage. >=20 >> Now you presented me with a third option. So you think I should skip = to create >> a new hardware-raid mirror and instead use two single drives and add = these as >> a mirror to the existing pool? >=20 > If you're going to keep the hardware raid, then setting up a new > hardware raid of two drives, and then striping da1 with da0 via zfs is > a viable option. It's just another spin on the RAID 10 idea. Ok. I think I'll go with this option for this machine. In the future I = would probably use a small SSD for booting and then use zfs for all raid-solutions.=20 >=20 >> How will zfs handle howswap of these drives? >=20 > ZFS doesn't know about your drives, because you hardware raid them. If > you set up the second hardware raid mirror as a striped drive in the > pool, and you then lose both drives within a single hardware raid > mirror set, you'll be in the drink. But that's the case with any RAID > 10 scenario. >=20 >> I've seen a few crashes due to ata-detach in other systems. >=20 > That's not a ZFS issue, that's a driver/support issue with the = controller. >=20 > -Sean >=20
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?FCABED3C-A1BC-4B72-9289-C16BAD4F6B39>