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Online Capacity

Doubrava Roman
Occasional Visitor

Online Capacity

Hallo,

My Server is a Netserver LH 4.
I have 4 x 9GB Drives as 1 Logical Drive on the integrated Netraid Controller with Raid 5. One 6 GB Partition and one 17 GB Partition.
I will activate the online Capacity, can i do it without loss of data ?
Can i change between Raid Levels without loss of Data ?
Then i will add a 1 x 36GB Drive to the one logical Drive does it work ?
After adding the drive (if its possible) can i expand the 17 GB Prtition with the 36GB ?
I have MS WinNT, if i couldn't add the drive, can i use NT Disk Admin to create a Volume over the 17GB Partition mixed with the 36GB Drive without loss of Data ?
4 REPLIES
Chris Blumenshine
Trusted Contributor

Re: Online Capacity

You can do capacity expansion to an array with out loss of data. However, if you add a 36gb drive to an array with 9gb drives, then the 36gb drive will become a 9gb drive, thus wasting 27gb of space. No way around it with that raid controller.

Other option: You can create another ???array??? with only the one 36gb drive, RAID 0. It will show up as another logical disk within Disk Administrator. Now I???m a hardware guy, not a NT guy, so I don???t know if you can create a volume set between the 17gb partition and the new 36gb partition without loosing data (I assume you can). If you do, however, you will negate the redundancy of the partition. That is, if the 36gb drive fails, you will loose the entire volume set/the entire partition. Only recovery at this point is from backup.

Safer option: create a RAID 1 with 2X 36gb drives, and then create the volume set. That way, if one of the 9gb drives in the RAID 5 fails, or if one of the 36gb drives in the RAID 1 fails, then your partition is still safe.

Also, you can change some raid levels. Just depends on from what level to what level. For instance, you can change a RAID 1 to a RAID 5, if you add another drive. You can change from a RAID 5 to a RAID 0 if you desire. You cannot change from a RAID 0 to a RAID 5 without adding another drive. Just depends what you have in mind...
There's always room for J-E-L-L-O
Doubrava Roman
Occasional Visitor

Re: Online Capacity

Hi, first thanks a lot of your quick answer.

RE: If you do, however, you will negate the redundancy of the partition. That is, if the 36gb drive fails, you will loose the entire volume set/the entire partition. Only recovery at this point is from backup.

I think my Idea is dirty, because if I mix Raid 5 and Raid 0 with the help of NT Disk Admin some Data of the Raid 5 drives could be placed on the Raid 0 Drive and reverse, i think my whole logical Drive could fail under such conditions.
Have someone experience with this problem ?

Other Question: Is Online Capacity only possible with same Drives and same Raid Levels ?


Terri Harris
Honored Contributor

Re: Online Capacity

1. Online capacity is not "enabled". It IS available as long as the RAID array (such as a RAID 5) was created as one logical drive.
2. If a RAID 1 and a RAID 5 array exists, NT will see these as two separate physical drives. This is also assuming the RAID 1 was created as a single logical drive (this is done within the HP RAID software).
3. Online capacity is done based on a single RAID array, such as a RAID 5. Since a RAID 1 consists of 2 (and exactly 2) physical drives, it is NOT possible to do online capacity with a RAID 1. This can be done with a RAID 0 or RAID 5.
4. Doing online capacity is very safe, but you should still have a good backup (just in case). Converting RAID arrays, such as converting a RAID 0 to a RAID 5, is also a safe operation. You can also convert a RAID 1 to a RAID 5 (a RAID 5 must contain at least 3 hard drives).
Doubrava Roman
Occasional Visitor

Re: Online Capacity

What's about my existing Partitions and creation of a Volume or Online Capacity over 2 different Raid Levels ?

1 Array, 4x9GB Raid 5, 2 Partitions 17GB,6GB
1 Array, 2x36GB Raid1, empty

can I activate online Capacity on the first Array and add the empty Space from the second Array. I want expand only the 17GB Partition.
Does it work without loss of Data.

If its not possible to do this with online Cap. can i use the NT Disk admin to Create a Volume over the 17GB Partition ?