Logical Drive "Ready for Rebuild" status on MSA20

[Dmitri Smirnov]

Today we have one of SATA drive replaced in brand new MSA20.

After replacement the RAID-5 rebuild process started for a first logical drive (2TB) but stopped at 5% and drive went to "Ready for Rebuild" status.

Rebuild process for a second logical drive (500GB) finished without problems.
Both logical drives are using same 12 SATA physc. drives.

I didn't get an exact response from HP support that it means and how to solve it.
Possible reasons I've heard are:
- activity on enclouse or logical drive (there is none) will pause the rebuild process
- read errors or potential failures reported by drives can suspend the rebuild process

Array diag. utility doesn't show anything wrong.

Can it happend because battery is reported "Low batteries, Recharging"?

Can I enforce the rebuild process?

BTW, I still able to access logical drives from OS (linux) but write performance is terrible.

Another small question: can I activate cache w/o batteries in MSA20?