Wolfgang Denk put forth on 1/26/2011 1:16 AM: > I will not have a single file system, but several, so I'd probably go > with LVM. But - when I then create a LV, eventually smaller than any > of the disks, will the data (and thus the traffic) be really distri- > buted over all drives, or will I not basicly see the same results as > when using a single drive? If creating multiple filesystems then concatenation is probably not what you want, for the reasons you suspect, if you want the IO spread across all 4 disks for all operations on all filesystems. > # lvcreate -L 32G -n test castor0 > Logical volume "test" created > # mkfs.xfs /dev/mapper/castor0-test Is this on that set of 4 low end Maxtor disks? Is the above LV sitting atop RAID 0, RAID 5, or concatenation? > [[Only 2/3 of the speed of XFS for block write, but nearly 20% faster > for block read. But magnitudes faster for file creates / deletes!]] Try adding some concurrency, say 8, to bonnie++ and retest both XFS and ext4. XFS was designed/optimized for parallel workloads, not single thread workloads (although it can extract some concurrency from a single thread workload). XFS really shines with parallel workloads (assuming the underlying hardware isn't junk, and the mdraid/lvm configuration is sane). ext4 will probably always beat XFS performance with single thread workloads, and I don't believe anyone is surprised by that. For most moderate to heavy parallel workloads, XFS usually trounces ext4 (and all other Linux filesystems). -- Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
