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Replace disks with higher capacity disks in Raid1+0 ...

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Occasional Contributor

Replace disks with higher capacity disks in Raid1+0 ...

Could someone help me to find a solution ?

Caracterisitics of the server :
Proliant DL380
Smart Array 5i Controller in Embedded Slot
Windows 2003 server

This server is configured like this :
-1 Array A with 4 drives of 36.4 Gb each one (2 disks Ultra3 SCSI and 2 disks Ultra 320 SCSI)

My collegue has create 3 Logical Drives :
- LD1 (8189Mb, Raid1+0) = C:\System
- LD2 (5119Mb, Raid1+0) = E:\Swap
- LD3 (56143Mb, Raid1+0) = D:\Data

We need to increase the capacity of D:\Data, and thus we've bought 2 disks of 72 Gb to replace 2 disks of 36 Gb!!!

Is it possible to replace a disk (36Gb)(in Raid1+0) with a higher capacity disk (72Gb), let hem to rebuild mirror and replace another disk with the second 72 Gb disk... ?
And what with the remaining free space ?

I suppose I dream but I need confirmation that this wouldn't work to decide to reinstall the server !!

But another idea is welcome !!!

PS : I am new in this field !!
Uwe Zessin
Honored Contributor

Re: Replace disks with higher capacity disks in Raid1+0 ...

I'm sorry, but that will not work. The total usable size of a disk array is limited by the smallest physical disk in that array. If you just replace two disks you will not gain any more space, because the remaining 36 GByte on each 72 GByte disks are unused..

If you expand your disk array by the two 72 GByte disks (that will make an array of 6 physical disks) you can extend your LD3 by 36 Gbyte. I am not sure if you can transparently replace all four disks with 72 GByte modells - perhaps somebody else has experience with the 5i controller - I have read that it works on some others.

You could also make a separate array with both 72 GByte disks, but you won't win much more space if you want to keep everything on one logical disk and the data is mirrored on only two drives, which could not be enough for your I/O requirements.
Andy McCreath
Frequent Advisor

Re: Replace disks with higher capacity disks in Raid1+0 ...

Hi, Uwe is quite correct thus far.
The usable capacity will remain @ 36GB, you will have to replace all 4 drives and expand the array when you have all the 72GB HDD's in place.

Then you will need to allocate the physical space n to your logical drives (or whatever you choose) and run diskpart from the cmd prompt (or use a tool like Partition Magic.

Good Luck,