On 16 Listopad 2011, 2:21, Cody Caughlan wrote: > How did you build your RAID array? Maybe I have a fundamental flaw / > misconfiguration. I am doing it via: > > $ yes | mdadm --create /dev/md0 --level=10 -c256 --raid-devices=4 > /dev/xvdb /dev/xvdc /dev/xvdd /dev/xvde > $ pvcreate /dev/md0 > $ vgcreate lvm-raid10 /dev/md0 > $ lvcreate -l 215021 lvm-raid10 -n lvm0 > $ blockdev --setra 65536 /dev/lvm-raid10/lvm0 > $ mkfs.xfs -f /dev/lvm-raid10/lvm0 > $ mkdir -p /data && mount -t xfs -o noatime /dev/lvm-raid10/lvm0 /data
I'm not using EC2 much, and those were my first attempts with ephemeral storage, so this may be a stupid question, but why are you building a RAID-10 array on an ephemeral storage, anyway? You already have a standby, so if the primary instance fails you can easily failover. What are you going to do in case of a drive failure? With a server this is rather easy - just put there a new drive and you're done, but can you do that on EC2? I guess you can't do that when the instance is running, so you'll have to switch to the standby anyway, right? Have you ever tried this (how it affects the performance etc.)? So what additional protection does that give you? Wouldn't a RAID-0 be a better utilization of the resources? Tomas -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
