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Question about RAID5

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Luis Ribas
Occasional Visitor

Question about RAID5

Hi everyone,

we've got a problem with our server, a proliant ml350 g3 with three HD mounted on RAID 5, one of those just broke so I just changed for a new one.

As the serv starts, a message appears showing that a new hd has been installed, giving me the option to choose between pressing F1 to continue without activating logical partition or F2 to re-enable logical partition with possible data loss.

As far as I know with RAID5, there shouldn't be any data loss, but I'm not sure, can anyone explain me if that's correct?. If not, is there any way to restore the serv without data loss?

thanks!
7 REPLIES
Brian_Murdoch
Honored Contributor

Re: Question about RAID5

Hi Luis,

Remove the new drive and boot the system with the two existing raid 5 drives. You will get a message to say that a disk is missing at SCSI ID=X and to continue.

Once the operating system is up and running insert the new drive. It should automatically start the rebuild once up to speed (disk led will flash about every second indicating that it is rebuilding).

To monitor the progress of the rebuild run ACU (Start-Programs-HP System Tools-HP Array Configuration Utility).
Select the logical drive and then click "More Information". A percentage completion bar should appear at the bottom of the screen indicating the rebuild progress.
Be aware that when you run ACU the disk lights will all come on. This is normal to indicate the logical drive you have selected in ACU. When you exit ACU they will go off again. Once the light has stopped flashing on the replacement disk it has rebuilt.

I hope this helps.

Brian
Luis Ribas
Occasional Visitor

Re: Question about RAID5

thanks, Im on it, but there's just a little problem... now that I've removed the hd, the server doesn't start, as it attempts to boot from hd, seems that the serv doest recognize it or something...

"Non-System disk or disk error, replace and strike any key when ready"

theres no error hd-led if it helps.
Brian_Murdoch
Honored Contributor

Re: Question about RAID5

Hi,

Are you sure you chose the correct option when prompted for F1 or F2 ?

One of them disables the logical drive and it can't be seen to boot. Go back, reboot and select the one which says "accept changes and continue".

I hope this helps.

Brian
Luis Ribas
Occasional Visitor

Re: Question about RAID5

great!, now just one more thing.

Just noticed that its not "possible data loss", its "Select "F2" to ACCEPT DATA LOSS and to re-enable logical drive(s)".

wich data is lost? I mean, I know that in RAID5, blocs are striped between the drives, so for example(not sure);

In Drive 1 theres block 1&2, in Drive 2 theres block 1 and in Drive 3 theres block 2.

So if thats true, as I can get, when I'll accept F2, as the Drive 1 is "removed", Block 1&2 are also removed, but.. when we start windows, data still remain in the other hds, so, is it able to be restored as I put the new hd?

thanks a lot!!
Brian_Murdoch
Honored Contributor
Solution

Re: Question about RAID5

Hi,

When a drive is missing, the raid controller is used to calculate the missing "stripe" so performance is degraded until the replacement drive has rebuilt.

Your operating system should boot OK but performance will be poorer until the replacement disk rebuilds. Once rebuilt, the load is taken off the controller and performance should be good again.

Brian
Luis Ribas
Occasional Visitor

Re: Question about RAID5

OK, Thanks for everything ^^
Bhavnish
Frequent Advisor

Re: Question about RAID5

Hi Luis,

The data which will in the BBWC will lost if you press the F2 key. There is no data will lost from your HDD.
Everything is Possible+++