On Sat, 27 Dec 2008, Josef 'Jeff' Sipek wrote:

On Thu, Dec 25, 2008 at 06:46:37PM -0500, Justin Piszcz wrote:

quoted

On Fri, 26 Dec 2008, Michal Soltys wrote:

quoted

quoted

I am not worried about the filesystem as the defaults usually get it right
but with parted, this is the first time I had to use it for home use and
with RAID-6 I am noticing slower performance with 15 disks (1 is a spare)
in RAID-6 (albeit slower 7200 ones, RE3s) than I was getting with 10
raptor150s in RAID-6 (but I had used fdisk there).

Justin.

For best effect - partition should start at 1920th sector (stripe width
boundary), and su/sw should be appropriately set - su=64k,sw=13 in your
case. Parted shows the values normally - from the beginning of the volume, 0
based.


ps.

I dropped some of CCs.

Thanks.

It looks like you made why big partition. Why bother with partitioning at
all? If you just use the whole device, you _will_ be aligned properly if you
tell mkfs.xfs about the stripe unit/width.

Josef 'Jeff' Sipek.

Why bother partitioning?  I also run a Linux SW RAID1 on the host, as you 
know the drive letters can change when working on a server.

Example: Before I created the array (RAID-6), my disks were /dev/sda, 
/dev/sdb and /dev/sdc (spare), the RAID-6 was /dev/sdd.  After reboot, 
/dev/sdd became /dev/sda and /dev/sd[a-c] became /dev/sd[b-d].

In lilo.conf I had:
raid-extra-boot="/dev/sda,/dev/sdb"

If I ran LILO and forgot to fix the lilo.conf to reflect the new drive 
mappings:
raid-extra-boot="/dev/sdb,/dev/sdc"

I could be at risk of ruining the partition?

I try to avoid such situations when possible, to be safe.

Justin.