Extending Volume Set

[Ayman Altounji]

We have a Proliant DL380 comprised of an array with a Raid 1 mirror set of 2 x 36gb drives. We have the logical drive partitioned under NT into a C: and a D: drive. We would like to increase the capacity of the D: drive and have purchased 2 X 36gb. We would like to set these up as another Raid 1 mirror set. Would we add the drives and create another array with another Raid 1 mirror set (logical drive) and then in NT create an expanded volume set? If we do this, if one of the drives in either of the mirror sets fails we should still have redundancy even though the expanded volume is comprised physically of all the drives. Am I right?

[Ayman Altounji]

you are a 100% right !!

if both arrays are set to raid 1your system can handle 1 failed disk in each array, so you have a high chance to even survive a double disk failure.

ernesto from germany

[Ayman Altounji]

First, are you software partitioning this RAID set using NT. Software partitioning of any smart array drive is highly unrecommended instead you should hardware partition it using the Array Config Utility. Next, If you are looking to stay equally as redundant add your new drives to the existing RAID set and modify it to a RAID 0+1 set (its a Smart Array it will let you do this). The reason I recommend you doing this is because you are essentially creating two mirror sets and then striping across your mirrors giving you much faster read/write performance (potential is double realistic is 40-60 faster) and it still protects you against a drive failure in either mirror set. This is assuming that these are the same size and same speed as the previous drives, ie 36GB 10k rpm. The added size will not show up to NT 4.0 until you increase the hardware partition size using the Array Config Utility and reboot the server. As with any changes that are made make sure you have a current backup, just in case. I have done this numerous times with no problems at all. Just a side note with the Smart Array you can do some really slick things like migrate your RAID sets to newer faster models of the Array controller, modify the RAID sets, ie RAID 1 to RAID 5 and it has DAS to SAN functionality with the MSA1000.