Hi there, I've discovered that most of the hard drives used in our cluster got misaligned partitions, thus crippling perfs. Is there any way to fix that without having to delete/recreate properly aligned partitions, then format it and refill disks ? I'd be glad not to have to toy with moving several 10s of TB disk by disk :D (most disks are JBOD as we're using a fault tolerant network FS, moosefs not to name it). <insert your favorite search engine> wasn't helpful, unfortunately. Drives are ext4, driven by C6 x86_64. Thanks, Laurent.
On 12/12/2012 09:36 AM, Laurent Wandrebeck wrote:> I've discovered that most of the hard drives used in our cluster got > misaligned partitions, thus crippling perfs. Is there any way to fix > that without having to delete/recreate properly aligned partitions, then > format it and refill disks ? > I'd be glad not to have to toy with moving several 10s of TB disk by > disk :D (most disks are JBOD as we're using a fault tolerant network > FS, moosefs not to name it).The data is going to have to be moved. There's just no way around it, and shifting it a few sectors one way or the other is going to be no faster, and a lot more dangerous, than copying it to a new partition. Copying to a different drive should be somewhat faster than copying to the same drive since neither drive needs to share its controller with both the read and write streams. -- Bob Nichols "NOSPAM" is really part of my email address. Do NOT delete it.
On Wed, Dec 12, 2012 at 9:36 AM, Laurent Wandrebeck <l.wandrebeck at gmail.com> wrote:> > I've discovered that most of the hard drives used in our cluster got > misaligned partitions, thus crippling perfs. Is there any way to fix > that without having to delete/recreate properly aligned partitions, then > format it and refill disks ? > I'd be glad not to have to toy with moving several 10s of TB disk by > disk :D (most disks are JBOD as we're using a fault tolerant network > FS, moosefs not to name it). > <insert your favorite search engine> wasn't helpful, unfortunately. > Drives are ext4, driven by C6 x86_64.Hmmm, might be a fun test of your fault-tolerance to remove disks one at a time and add them back empty with the partitions properly aligned. Maybe... -- Les Mikesell lesmikesell at gmail.com
On Wed, Dec 12, 2012 at 4:36 PM, Laurent Wandrebeck <l.wandrebeck at gmail.com> wrote:> Hi there, > > I've discovered that most of the hard drives used in our cluster got > misaligned partitions, thus crippling perfs. Is there any way to fix > that without having to delete/recreate properly aligned partitions, then > format it and refill disks ? > I'd be glad not to have to toy with moving several 10s of TB disk by > disk :D (most disks are JBOD as we're using a fault tolerant network > FS, moosefs not to name it). > <insert your favorite search engine> wasn't helpful, unfortunately. > Drives are ext4, driven by C6 x86_64.boot the server with a gparted livecd / pxe ; move the partitions around with an offset of 1MB at the start of the disk/volume. I do not know if this trick will work with lvm, in this case you need to move the data around and recreate the volumes with the correct offset. Have fun! -- groet, natxo