Greg Smith wrote:
Richard Neill wrote:
3. RAID 0 is twice as unreliable as no raid. I'd recommend using RAID 1
intead. If you use the Linux software mdraid, remote admin is easy.
The main thing to be wary of with Linux software RAID-1 is that you
configure things so that both drives are capable of booting the system.
It's easy to mirror the data, but not the boot loader and the like.
Good point. I actually did this on a home PC (2 disks in RAID 1). The
solution is simple: just "grub-install /dev/sda; grub-install /dev/sdb"
and that's all you have to do, provided that /boot is on the raid array.
Of course, with a server machine, it's nearly impossible to use mdadm
raid: you are usually compelled to use a hardware raid card. Those are a
pain, and less configurable, but it will take care of the bootloader issue.
Obviously, test it both ways.
7. If you have 3 equal disks, try doing some experiments. My inclination
would be to set them all up with ext4...
I have yet to yet a single positive thing about using ext4 for
PostgreSQL. Stick with ext3, where the problems you might run into are
at least well understood and performance is predictable.
I did some measurements on fdatasync() performance for ext2,ext3,ext4.
I found ext2 was fastest, ext4 was twice as slow as ext2, and ext3 was
about 5 times slower than ext2. Also, ext4 is doesn't having an
appallingly slow fsck.
We've had pretty good results from ext4.
Richard
--
Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
