Date: Sat, 30 Oct 2010 13:11:46 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Peter =?iso-8859-1?Q?Ankerst=E5l?= <peter@pean.org> Cc: freebsd-fs@freebsd.org Subject: Re: Raid + zfs performace. Message-ID: <20101030201146.GA63194@icarus.home.lan> In-Reply-To: <C10169FF-72DA-409E-A741-E827FF894B85@pean.org> References: <D2954020-C3A0-46EC-8C64-EB57EA1E9B21@pean.org> <AANLkTinQWchAPtcqcO3mDt9gKK5tCsHo8khyiD69M4BV@mail.gmail.com> <86693036-9351-4303-BADA-C99F7A4C375C@pean.org> <AANLkTima02fBo8gRwCTZH3xWV1mM3r439tgQCXVa4RwB@mail.gmail.com> <C10169FF-72DA-409E-A741-E827FF894B85@pean.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, Oct 30, 2010 at 09:13:41PM +0200, Peter Ankerstål wrote: > > > > > >> 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? > > > > 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. > > > Sorry to ask again but I'm still not sure what you think is the best solution when > comparing adding the two new drives as a zfs mirror like: > pool > da0 > mirror > da1 > da2 > > or making a hardware mirror da1 and adding that one > > pool > da0 > da1 The answer is "it depends", and I can't authoritatively act as your system administrator since I don't have any familiarity with what it is your systems are doing and so on. That's your job. :-) You'd need to disclose exactly: - What hardware RAID controller you're using and all of its capabilities, including if it has cache and a BBU, - Full details of the workload on the machine and what the majority of I/O consists of, - What exact OS you're running (uname -a please) and how much physical RAM the system has. If you really want to answer your own question, I would recommend at least performing benchmarks (bonnie++ might suffice) with both setups. And don't forget that if you use ZFS you'll need to perform some minor loader.conf tuning, and expect to adjust values depending on workload/environment. > And by the way. you guys seem zfs-shifty. Language barrier detected! :-) "ZFS-shifty" could mean either "you're ZFS advocates (fans of ZFS and recommend using it over anything else)", or "you're timid when it comes to/afraid of ZFS". I think you meant the first one, but I'm not certain. If so: believe it or not, I'm not much of a FreeBSD ZFS advocate. There are issues that keep appearing on the mailing lists (-stable and -fs), and each incident has to be handled individually. There are definitely stability issues (we just experienced one ourselves which was major[1]; it's been fixed in RELENG_8 since mid-October) which are still getting hammered out. My logic is this, and this is just one man's opinion: - If you need absolute stability, don't have time or the desire to tinker with new technology (or have 100% mission-critical services in use), stick with using UFS + softupdates. - If filesystem administrative simplicity is needed over everything else, ZFS is an excellent choice. - If you want ZFS and need absolute rock-solid performance, stability, and It Should Just Work(tm), run Solaris 10 or OpenSolaris. - If you're going to use ZFS on FreeBSD, you need to run RELENG_8, and should almost certainly be running amd64, and have at least 4GB RAM. > Do you have any ideas about my other problem i posted to the list? > (http://lists.freebsd.org/pipermail/freebsd-fs/2010-October/009922.html) Nope, I don't. I don't use ZFS send/recv nor snapshot capability. I do keep seeing problems reported with both of these on the lists, but again, they have to be handled on a per-case basis. [1]: http://lists.freebsd.org/pipermail/freebsd-fs/2010-October/thread.html#9687 ("Locked up processes after upgrade to ZFS v15") -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20101030201146.GA63194>