RAID migration

 
MGaccess
Frequent Advisor

RAID migration

I have a Win 2003 DL380 with 2 RAID1 arrays and 642 controller.

Array B has one logical drive and I want to add two drives (to total 4 146GB drives) and migrate it to a RAID 5 set. I added the two drives to the array and successfully migrated it to RAID 5.

Now I want to Extend the 140GB logical drive to the new "unused" space which is 373GB. When I begin to extend the drive, it says the maximum I can make it is 261GB. Why is that? Why can't I extend it over the full "unused" space? Any thoughts? (snapshot is attached)
2 REPLIES 2
amhakassa
Honored Contributor

Re: RAID migration

Hi Michael,

It sounds right for me. I will try to explain

At first you had a logical drive size of 146GB from your previous RAID 1
When you migrate the logical drive to RAID 5, the logical drive size remains the same 146GB (which will be distributed over the 4 drives) 146 / 4 = 48.67 meaning this is the size that will be used from each drive. This leaves the available disk size from each drive as 146GB - 48.67GB = 97.33GB (which now is available as unsued space approximatly 4 * 97.33GB = 389.82GB)

When you extend the logical drive one fourth of the unused space which is 97.33GB will be reserved for redundancy so
389.82GB - 97.33GB = 291.99GB will be the max you can go is apprximatly 291.99GB which is close to what you have been told by the expansion process.

I hope this will explains it

If you have more question or it is not clear let me know

Regards
Amha Kassa
MGaccess
Frequent Advisor

Re: RAID migration

Thanks. It worked. One thing to note is that version 7.0.1 or earlier of the Config Utility will not allow you to extend a logical volume past 260GB. I had to download the newest version to gain that ability. -Mike