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ML310 G5 Raid rebuild times.

Doug Gelling
Advisor

ML310 G5 Raid rebuild times.

As a test I removed a HD from my RAID 1 set on a ML310 G5. As expected the storage manager told me that the array was degraded. I then replaced the drive with another one I had and waited for the array to rebuild.
I started the rebuild at 14:20 local time, now at 10:00, the following day, it shows 52% complete.
Does anyone have any experience on how long a SATA raid 1 rebuild on a 250GB drive should take?
It only took 75 minutes to created the array from the BIOS utility.
This machine is just sitting there with nothing else running on it. It's going live this weekend.
8 REPLIES
KarloChacon
Honored Contributor

Re: ML310 G5 Raid rebuild times.

hi

are you using the HP SATA manager software to monitor that?


regards
Didn't your momma teach you to say thanks!
Doug Gelling
Advisor

Re: ML310 G5 Raid rebuild times.

Yes I am using the HP Storage Management software to monitor the rebuild. It finally finished at 04:05 local time today. A total elapsed time of 37 hours 45 minutes.

Given that an offline rebuild of the array only took 75 minutes, I know which one I'll be using in the future.
KarloChacon
Honored Contributor

Re: ML310 G5 Raid rebuild times.

oh I forgot to tell you

the there is an option to enable cache that will increase the speed

my bad


regards
Didn't your momma teach you to say thanks!
IBaltay
Honored Contributor

Re: ML310 G5 Raid rebuild times.

Hi,
the reason for the background operations are slower in all array controllers (storages included - e.g. MSA, EVA, XP) is that the high priority is always the IO. Thus the IO utilisation then impacts the speed of any background operation.
the pain is one part of the reality
Doug Gelling
Advisor

Re: ML310 G5 Raid rebuild times.

Karlo, enabling the write cache seems to have done the trick.
I enabled it then pulled a drive and put it back in, after 16 minutes rebuild is 15% complete. Much better.
One question, is there an issue of enabling the write cache without some sort of independent battery backup?
I know most of the addon RAID cards have this as an option.
The server has dual power supplies and both will be plugged into different UPS's so not too worried about a power failure.
Also do you know what memory the system uses for the write cache? Is it system memory or memory on the drives?

Thank You
Doug
KarloChacon
Honored Contributor

Re: ML310 G5 Raid rebuild times.

jeje

cool the test you did I mean enable cache and rebuild HDD again ;-)

"One question, is there an issue of enabling the write cache without some sort of independent battery backup?"

yes when cache is enabled is recommended to have power redundancy - dual power supply or UPS, that's the recommendation from HP

so if the there is not power redundancy information in cache can be corrupted meaning data lost.


"Also do you know what memory the system uses for the write cache? Is it system memory or memory on the drives?"

this cache is located in the controller(part of the System Board) not in the HDDs

I hope this info can help you

anything else let me know
bye
Didn't your momma teach you to say thanks!
Doug Gelling
Advisor

Re: ML310 G5 Raid rebuild times.

Karlo, thank you for the additional information. Rebuild completed in 100 minutes. A much better option than the 38 hours the first one took.

Doug Gelling
Advisor

Re: ML310 G5 Raid rebuild times.

Thread closed