Messages in this thread | | | From | Niels <> | Subject | Re: Slow disks. | Date | Sun, 26 Dec 2010 23:07:45 +0100 |
| |
On Friday 24 December 2010 16:24, Michael Tokarev wrote:
[snip] > The thing is, for these WD*EARS drivers, it is _vital_ to get > proper alignment of all partitions and operations. They've > 4Kb sectors physically but report 512bytes sectors to the OS. > It is _essential_ to ensure all partitions are aligned to the > 4Kb sectors. Be it LVM, raid-something, etc - each filesystem > must start at a 4kb boundary at least, or else you'll see > _dramatic_ write speed problems. > > So.. check the whole storage stack and ensure proper alignment > everywhere. In particular, check that your partitions are not > aligned to 63 sectors (512b), or starts at N+1 sector - the > most problematic mode for these drives. [snip]
I have several of these drives, in various sizes. They seem to be aligned to 63 as you mention:
Device Boot Start End Blocks Id System /dev/sda1 63 208844 104391 83 Linux /dev/sda2 208845 19759949 9775552+ 82 Linux swap / Solaris /dev/sda3 19759950 215094284 97667167+ 83 Linux /dev/sda4 215094285 781417664 283161690 83 Linux
Device Boot Start End Blocks Id System /dev/sdb1 63 1953520064 976760001 83 Linux
Is that bad?
What can I do to repair it?
What can I do to prevent it from happening again?
Thanks, Niels
| |