Dear All, got a hardware q.
Most of our important servers have a pair of Linux software RAID1 OS
disks. In looking into buying spares, it's impossible to match specs - for
instance our Viglen servers came with 2 x WDC WD2500YS-01S = 16MB, AvgLat
4.2, AvgSeek 8.7, Internal Data Rate 70MBps.
You simply can't buy a match, new disks have much faster Internal Data
Rate. The old-ish 250GB replacement we have on hand is a WD2502ABYS with
same buffer, AvgLat & close AvgSeek, but an Internal Data Rate of 126MBps.
A set of other 250GB disks (at Insight) all only have 8MB Buffer, similar
AvgLat & AvgSeek (altho some up to 14ms) but Internal Data Rates varying
95-110-125MBps to 140MBps.
In such close work as RAID1, how much will those differences matter, or
will the faster disk throttle back to match its slower older mate? And
what about an 8/16 difference in buffer size? Bad or doesn't matter?
It would be bad for the RAID1 to become unstable.
An option is to have 2 spares, remove damaged drive, sync with
replacement, then also remove the other old one & replace with new &
resync so the RAID1 pair is always identical disks. Safest, or just
unecessary work/caution?
Grateful for enlightenment.
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