On Sat, Jul 13, 2013 at 01:43:40AM +1000, Russell Coker wrote:
On Fri, 12 Jul 2013, Colin Fee <tfeccles@gmail.com> wrote:
So I'm looking for a strategy re the implementation of ZFS. I can install up to 4 SATA disks onto the mobo (5 in total with one slot used by the SSD)
Firstly plan what you are doing especially regarding boot.
Do you want to have /boot be a RAID-1 across all 4 of the disks?
not a good idea with ZFS. Don't give partitions to ZFS, give it entire disks. from the zfsonlinux faq: http://zfsonlinux.org/faq.html#PerformanceConsideration "Create your pool using whole disks: When running zpool create use whole disk names. This will allow ZFS to automatically partition the disk to ensure correct alignment. It will also improve interoperability with other ZFS implementations which honor the wholedisk property."
Do you want it just on the SSD?
much better to do it this way, which is one of the reasons I suggested a second SSD to have mdadm raid-1 for / and /boot.
Don't bother with ZIL or L2ARC, most home use has no need for more performance than modern hard drives can provide and it's best to avoid the complexity.
if he's got an SSD then partitioning it to give some L2ARC and ZIL is easy enough, and both of them will provide noticable benefits even for home use. it takes a little bit of advance planning to set up (i.e. partitioning the SSD and then issuing 'zfs add' commands, but it's set-and-forget. doesn't add any ongoing maintainence complexity. e.g. here's the 'zfs history' from when I installed my old SSD in my myth box after upgrading the SSD on my main system. it had previously been running for almost a year without L2ARC or ZIL (but with 16GB RAM, just because I had some spare RAM lying around) 2013-04-09.09:59:01 zpool add export log scsi-SATA_Patriot_WildfirPT1131A00006353-part5 2013-04-09.09:59:07 zpool add export cache scsi-SATA_Patriot_WildfirPT1131A00006353-part6
On Fri, 12 Jul 2013, Kevin <kevin@fuber.org> wrote:
You need 4GB min for a reasonable zfs server plus more if you use dedupe
I've had a server with 4G have repeated kernel OOM failures running ZFS even though dedupe wasn't enabled. I suggest that 8G is the bare minimum.
i'd agree with that. I haven't had the OOM failures even on 4GB (possibly because i've always used ZFS with either 8+GB or with some SSD L2ARC) but ZFS does benefit from more RAM.
On Fri, 12 Jul 2013, Craig Sanders <cas@taz.net.au> wrote:
0. zfsonlinux is pretty easy to work with, easy to learn and to use.
Actually it's a massive PITA compared to every filesystem that most Linux users have ever used.
yeah, well, it's a bit more complicated than mkfs. but a *lot* less complicated than mdadm and lvm. and gaining the benefits of sub-volumes or logical volumes of any kind is going to add some management complexity whether you use btrfs(8), zfs(8), or (worse) lvcreate/lvextend/lvresize/lvwhatever.
You need DKMS to build the kernel modules and then the way ZFS operates is very different from traditional Linux filesystems.
dkms automates and simplifies the entire compilation process, so it just takes time. it's not complicated or difficult. or you could just use the zfsonlinux binary repo for the distribution of your choice and install a pre-compiled binary. for debian, instructions are here: http://zfsonlinux.org/debian.html craig -- craig sanders <cas@taz.net.au> BOFH excuse #54: Evil dogs hypnotised the night shift