On 7/8/07, Johnny Hughes <johnny@xxxxxxxxxx> wrote:
Well ... if you are using hardware RAID, then striping LVM will likely not give you any benefit speed wise. (Unless multiple controllers are used and read/write can be done in parallel). The speed benefit happens if LVM can stripe the sectors to SATA or SCSI drives where simultaneous read/writes can happen. With hardware RAID, the controller normally handles all that, so LVM striping is not normally done.
What we have is a hardware RAID enclosure that already has all the drives it can handle, and is approaching capacity. So what we're currently considering is adding an entire additional RAID device and using LVM to combine them into a VG as a pair of SCSI drives. So it appears we could configure them as either striped or linear, and LVM2 would handle growing even a striped configuration if we add a third RAID later. A performance boost from LVM striping would be a bonus, but what I'm really asking is whether there's a penalty for LVM linear. I hadn't considered, though, that we could also rotate larger drives into the existing RAID and then grow the filesystem once they were all upgraded. _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos
