> On Mon, 12 Sep 2005 at 8:42am, Francois Caen wrote > > > On 9/12/05, Joshua Baker-LePain <jlb17 at duke.edu> wrote: > > > As I mentioned, I'm running centos-4, which, as we all know, is based > off > > > RHEL 4. If you go to <http://www.redhat.com/software/rhel/features/>, > > > they explicitly state that they support ext3 FSs up to 8TB. > > > > Wow! Odd! RH says 8TB but ext3 FAQ says 4TB. > > I wouldn't call it that odd. RH patches their kernels to a fair extent, > both for stability and features. > > > >From my personal testing on CentOS 4.1, you can't go over 4TB without > kludging. > > > > > I then did a software RAIDO across them, and finally: > > > > > > mke2fs -b 4096 -j -m 0 -R stride=1024 -T largefile4 /dev/md0 > > > > Joshua, thanks for the reply on this. > > There's something kludgy about having to do softraid across 2 > > partitions before formatting. It adds a layer of complexity and > > reduces reliability. Is that the trick RH recommended to go up to 8TB? > > Err, it's not a kludge and it's not a trick. Those 2 "disks" are hardware > RAID5 arrays from 2 12 port 3ware 9500 cards. I like 3ware's hardware > RAID, and those are the biggest (in terms of ports) cards 3ware makes. > So, I hook 12 disks up to each card, and the OS sees those as 2 SCSI > disks. I then do the software RAID to get 1) speed and 2) one partition > to present to the users. Folks (myself included) have been doing this for > years. > > The one gotcha in this setup (other than not being able to boot from the > big RAID5 arrays, since each is >2TiB) is that the version of mdadm > shipped with RHEL4 does not support array members bigger than 2TiB. I had > to upgrade to an upstream release to get that support. Just out of interest, and to complicate the matter even more, does anyone know what the upper limit of GFS is?