> Hello, > > I'm quite interested in ZFS, like everybody else I > suppose, and am about > to install FBSD with ZFS. > > On that note, i have a different first question to > start with. I > personally am a Linux fanboy, and would love to > see/use ZFS on linux. I > assume that I can use those ZFS disks later with any > os that can > work/recognizes ZFS correct? e.g. I can > install/setup ZFS in FBSD, and > later use it in OpenSolaris/Linux Fuse(native) later?
I've seen some discussions that implied adding attributes to support non-Solaris (*BSD) uses of zfs, so that the format would remain interoperable (i.e. free of incompatible extensions), although not all OSs might fully support those. But I don't know if there's some firm direction to keeping the on-disk format compatible across platforms that zfs is ported to. Indeed, if the code is open-source, I'm not sure that's possible to _enforce_. But I suspect (and certainly hope) it's being encouraged. If someone who works on zfs could comment on that, it might help. > Anyway, back to business :) > I have a whole bunch of different sized disks/speeds. > E.g. 3 300GB disks > @ 40mb, a 320GB disk @ 60mb/s, 3 120gb disks @ 50mb/s > and so on. > > Raid-Z and ZFS claims to be uber scalable and all > that, but would it > 'just work' with a setup like that too? > > I used to match up partition sizes in linux, so make > the 320gb disk into > 2 partitions of 300 and 20gb, then use the 4 300gb > partitions as a > raid5, same with the 120 gigs and use the scrap on > those aswell, finally > stiching everything together with LVM2. I can't easly > find how this > would work with raid-Z/ZFS, e.g. can I really just > put all these disks > in 1 big pool and remove/add to it at will? And I > really don't need to > use softwareraid yet still have the same reliablity > with raid-z as I had > with raid-5? What about hardware raid controllers, > just use it as a JBOD > device, or would I use it to match up disk sizes in > raid0 stripes (e.g. > the 3x 120gb to make a 360 raid0). > > Or you'd recommend to just stick with > raid/lvm/reiserfs and use that. One of the advantages of zfs is said to be that if it's used end-to-end, it can catch more potential data integrity issues (including controller, disk, cabling glitches, misdirected writes, etc). As far as I understand, raid-z is like raid-5 except that the stripes are varying size, so all writes are full-stripe, closing the "write hole", so no NVRAM is needed to ensure that recovery would always be possible. Components of raid-z or raid-z2 or mirrors can AFAIK only be used up to the size of the smallest component. However, a zpool can consist of the aggregation (dynamic striping, I think) of various mirrors or raid-z[2] virtual devices. So you could group similar sized chunks (be it partitions or whole disks) into redundant virtual devices, and aggregate them all into a zpool (and add more later to grow it, too). Ideally, all such virtual devices would have the same level of redundancy; I don't think that's _required_, but there isn't much good excuse for doing otherwise, since the performance of raid-z[2] is different from that of a mirror. There may be some advantages to giving zfs entire disks where possible; it will handle labelling (using EFI labels) and IIRC, may be able to better manage the disk's write cache. For the most part, I can't see many cases where using zfs together with something else (like vxvm or lvm) would make much sense. One possible exception might be AVS (http://opensolaris.org/os/project/avs/) for geographic redundancy; see http://blogs.sun.com/AVS/entry/avs_and_zfs_seamless for more details. It can be quite easy to use, with only two commands (zpool and zfs); however, you still want to know what you're doing, and there are plenty of issues and tradeoffs to consider to get the best out of it. Look around a little for more info; for example, http://www.opensolaris.org/os/community/zfs/faq/ http://en.wikipedia.org/wiki/ZFS http://docs.sun.com/app/docs/doc/817-2271 (ZFS Administration Guide) http://www.google.com/search?hl=en&q=zpool+OR+zfs+site%3Ablogs.sun.com&btnG=Search This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
