|Chris Heerschap on 5 Mar 2013 06:58:29 -0800|
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|Re: [PLUG] Survey: Linux RAID mirror sync time|
I've seen rebuilds go quickly when done with fast, small SAS/SCSI disks. I've seen them go slowly with larger SATA disks. For example, on a dedicated storage system (IBM DS4500) we saw an 8 hour rebuild time on a 500GB SATA disk. Larger disks took a proportionally longer time. Unless the system is loaded, the rebuild time shouldn't change much either way based on the CPU type.
Conversely, a mirror rebuild on SSD should be really, really quick.Big, slow SATA drives are part of the reason why more redundant arrays like RAID-6 (or RAIDZ2 and RAIDZ3 on ZFS) are gaining popularity - rebuilds of really big disks can take so long that the possibility of a second drive fault goes up significantly. Drives are faster than old PATA drives, but also *significantly* bigger.
cmh On 3/4/13 7:36 PM, Eric at Lucii.org wrote:
Just curious what folk's experience is with this. If you replace one drive of a RAID mirror pair with a blank drive how long does it take to sync? Maybe 5 years ago I replaced a 160GB drive in such a configuration and as I recall the sync was about 2 hours. That was a 500 MHz Celeron with PATA drives. I believe that faster drives (SATA and even SAS) and faster chip sets and bus speeds may cancel out the penalty of larger drive sizes. I only ever had to sync a drive that one time so the data sample size is way too small :-)
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