> My problem is that LVM2 is not supported in parted which is the
> recommended tool to deal with this.
>
> I suspect I only need to map the individual PE to a particular start
> sector on each drive, not btrfs, but then there is stripe/block sizes to
> consider as well ... WD also are recommending 1mb sector boundaries for
> best performance - I can see a reinstall coming up :)
>
I have on my workstation:
2 WD 2TB Black Drives
5 WD 2TB RE4 Drives
Some notes:
- The black drives have horrible reliability, poor sector remapping, and have
certain standard drive features to make them unusable in raid. I would not
buy them again. I'm not sure how similar the green drives are.
- Many of the recent WD drives have a tendency to power down/up frequently
which can reduce drive lifetime (research it and ensure it is set
appropriately for your needs).
- Due to reliability concerns, you'll may need to run smartd to give adequate
pre-failure warnings
Anyhow, in my config I have:
1 RE4 Drive as Server Boot Disk
4 RE4 Drives in SW RAID10 (extremely good performance and reliability)
2 Black Drives in LVM RAID0 for disk-to-disk backups (thats about all I trust
them with).
When I setup the LVM RAID0, I used the following commands to get good
performance:
fdisk (remove all partitions, you don't need them for lvm)
pvcreate --dataalignmentoffset 7s /dev/sdd
pvcreate --dataalignmentoffset 7s /dev/sdf
vgcreate -s 64M -M 2 vgArchive /dev/sdd /dev/sdf
lvcreate -i 2 -l 100%FREE -I 256 -n lvArchive -r auto vgArchive
mkfs.ext4 -c -b 4096 -E stride=64,stripe_width=128 -j -i 1048576 -L
/archive /dev/vgArchive/lvArchive
I may have the ext4 stride/stripe settings wrong above, I didn't have my
normal notes when I selected them - but the rest of the config I scrounged
from other blogs and seemed to make sense (the --dataalignmentoffset 7s) seems
to be the key.
My RAID10 drives are configured slightly different w/ 1 partition that starts
on sector 2048 if I remember and extends to the end of the drive.
The 4 Disk SW RAID10 array gives me 255MB/s reads, 135MB/s block writes, and
98MB/s rewrites (old test, may need to rerun for latest changes/etc).
LVM 2 Disk RAID0 gives 303MB/s reads, 190MB/s block writes, and 102MB/s
rewrites (test ran last week).
Regards,
Matt
--
Matthew Marlowe / 858-400-7430 / DeployLinux Consulting, Inc
Professional Linux Hosting and Systems Administration Services
www.deploylinux.net * [email protected]
'MattM' @ irc.freenode.net
