Can I rebuild degraded RAID1 on a SAS 5 i controller with a larger mirror drive size?

Question

A drive failed on a Dell SAS 5i controller - see controller bios screengrab: http://imagebin.ca/view/SkZbszA.html

The primary is a 160GB 10k sata drive.

I added a 250GB 7k rpm drive in the hope that the array would rebuild onto this drive. This did not happen. (assuming that the controller would just operate at the speed of the slowest drive)

The controller could see the new drive, but it didn't automatically rebuild the raid1 onto this drive. (my assumption is that it did not do this rebuild as the drive sizes are different).

There was an option to add the new drive to the existing raid1 array - but when I tried this a message appeared stating that all data on the array would be lost. (I didn't get a screenshot of this message, I will later)

Should the SAS 5i allow me to rebuild the array onto a larger drive?

Is the option to add the drive to the array the right way to go?

Many thanks!

Solution

It should allow to rebuild onto a larger disk, how exactly did you try to initiate the rebuild? The proper way is to set the new disk as hotspare, and then a rebuild should start automatically

Comments

[Kenny]

The SAS 5i doesn't support a "Hot Spare". en.community.dell.com/support-forums/servers/f/906/p/1914949‌​4/…

[Kenny]

I can't see any mention of hot spares in the controller BIOS, and googling the terms it shows that the SAS 5IR doesn't seem to support hot spares. en.community.dell.com/support-forums/servers/f/906/p/1914949‌​4/… There's an option to "Add Disk" to the existing Array.. (imagebin.ca/view/skdg3Ym.html) but I'm worried about this possibly destroying the data on the original drive..

[Kenny]

I haven't tried OMSA, it's a desktop machine.. imagebin.org/101627 - there's "Manage Secondary Disk" from which I can add the new disk "imagebin.ca/view/skdg3Ym.html" - but I'm sure I can't see anything about hot spares..

[Kenny]

The Dell documentation talks about the option for managing the secondary disk in the IM volume... "Manage Secondary Disk This option is used to add a secondary drive to a degraded IM virtual disk with a missing member. " from: public.support.unisys.com/pcproducts/esx/docs/DellDocs5.4/en‌​/… My bios screenshots: imagebin.ca/view/skdg3Ym.html imagebin.ca/view/sgsoUdlC.html So is this safe to do in our case, which is a degraded IM virtual disk with a missing member...?

[Kenny]

Thanks for all your assistance - Dell support can't give me 100% if it'll work or not sadly.

[David Corsalini]

yeah, the safest solution is to backup, rebuild, and restore no matter how good your storage hw is :)