AX150i drive upgrades and system drive upgrades.

[dmandell]

We have an AX150i with 500gb drives.
The disk pools and virtual drives are all setup and running, etc.

If I want to upgrade the drives to 750gb drives, what happens when I replace a 500gb drive with a 750GB drive? (pull out a 500 and stick in a 750)

a. The "extra" space will just show as unconfigured available space?
b. The extra space will be added to existing virtual disk?
c. If the replaced drive is a "system drive", I will not gain any space at all?
d. If the replaced drive is a "system drive", same as "answer a."?
e. none of the above?

Thanks,
Dana

 

[dmandell]

Here is the answer from EMC.

Replacing a single drive (500GB --> 750GB) will not yield additional usable space, as space is allocated at the RAID group level. That is, if you had a RAID 5 grouping of 5 drives, the size of all 5 of the drives in the RAID group would need to be increased, such that extra space is available "across" the RAID group.

In situations where drives in a RAID group are different sizes, the effective "depth" of the RAID group is limited to that of the smallest drive (example - if creating a RAID 1 mirror between a 146GB drive and a 500GB drive; the usable space of each drive is 146GB, and the "extra" space on the 500GB drive is not accessible).

Thus in the example below, additional configureable space would be available when all drives in a particular RAID group have become larger. Specifics will depend on what RAID grouping is being used (e.g. a 2 drive mirror, or a 5 drive RAID 5, etc.), and such extra space should then appear as unconfigured available space.

Note - replacing every drive in an existing RAID group one-by-one is not a recommended procedure, as it creates an artificially long period of the time that the RAID group will be running without N+1 protection.

There it is!
Thanks to all that looked at this post and thought about replying.

DP