Re: RAID 1 (mirroring) question

On Wed, Dec 19, 2012 at 6:07 AM, Bob Proulx <bob@proulx.com> wrote:

Note that after a power cycle even if the RAID 1 array needs to be
sync'd between the mirrored disks that the system will still boot okay
and will operate normally. I have no idea what other systems do but
you can boot the system, log in, and it will perform its normal
tasks. If the array needs to be sync'd then it will sync in the
background. This is why the kernel implements the speed_limit_max
values so that normal system operation will not be starved of disk
bandwidth. You might not notice that it is doing this. It might
finish the task without impacting normal system functions.

with Windows 7, the system boots and I can use it but is very sluggish due to all that disk activity. Hoping linux will handle this situation better.

will try md RAID and see how it performs.

from man md page:

"While this recovery process is happening, the md driver will monitor accesses to the array and will slow down the rate of recovery if other activity is happening, so that normal access to the array will not be unduly affected. When no other activity is happening, the recovery process proceeds at full speed. The actual speed targets for the two different situations can be controlled by the speed_limit_min and speed_limit_max control files mentioned below. "

this sounds promising. I will also be building a BSD server and see how ZFS RAID handles these situations.

Thanks you very much for the detailed reply. It was very useful.
--
Kind regards,
Yudi