I was wondering what guidelines people are using for creating metavolumes. Does the space request need to be extremely large? I am wondering, if I have a 160G request, would it be better to create a metavolume(I) or not? If the customer requests metavolumes we will honor it but if they do not request it, we do not assign metavolumes unless the request is large like 1T. What would be the benefits/hindrances of assigning a met volume or not? If I do create metavolumes do I need to know how the VERITAS people will carve it up?
There are no set guidelines in a SAN as far as volume creation. This is true for software based volumes, and virtual LUNs carved from a storage array.
One benefit of using hardware based LUNs is there is no overhead on the host when accessing those LUNs. Metavolumes can be created using a variety of third party software, and offer the convenience of host-based control for sizing and dispersion either through or across hardware arrays. If your storage provider cannot provide hardware based LUNs of the size your users require, then it may be necessary to use a software based volume approach.
Performance is always paramount and spreading application load among as many spindles as possible will reduce hot spots. If the array can do this in hardware (like HDS does, 36Mb to 1.7TB volumes) then use the hardware for better performance. If you can spread out the volumes via software (VERITAS), then that would also be a benefit if your storage vendor cannot do it.Chris
This was first published in July 2001