On 08/12/17 20:48, noah pugsley wrote:
On Sat, Aug 12, 2017 at 10:55 AM, Federico Giannici
Is it possible to set a "Hot Spare" chunk for a RAID1 Softraid?
From the "bioctl" man page seems that this functionality is available for
"RAID controllers" only.
Is it correct?
I don't know about that, but from softraid(4) I know that:
A mirroring discipline. It copies data across more than one chunk to
provide for data loss. Read performance is increased, though at the
cost of write speed. Unlike traditional RAID 1, softraid supports the
use of more than two chunks in a RAID 1 setup."
So, why not a 3 disk mirror?
Good point, but now I have two more questions:
1) What about the "cost of write speed"? Will writing times increase
further with another disk? Is it negligible?
2) What happens when one of the three disk goes bad? Is it signaled in
any way? The softraid goes "degraded" or remains "Online" (I suppose the
"Configure softraid0 with 4 special devices (/dev/sd2e, /dev/sd3e,
/dev/sd4e, /dev/sd5e) and a RAID level of 1:
# bioctl -c 1 -l /dev/sd2e,/dev/sd3e,/dev/sd4e,/dev/sd5e softraid0"