1. Which tasks take the most time in managing a SAN and why?
2. Why is the area of SAN management so different from other enterprise storage management functions (or is it)?
3. What are some general guidelines/suggestions for someone trying to evaluate the various SAN management software offerings currently available?
1. This is an example of an "it depends" question because it depends on the size of the SAN and the type of storage applications running over it. In general I would say provisioning storage resources and connections in an operating SAN. When I say provisioning I refer to the sequence of state changes that must be done while ensuring safe, unobstructed access between all the existing systems and storage. It takes careful planning and double-checking to make sure you don't screw something up. It takes constant checking and testing to ensure that each step had the result expected before moving on to the next step. It's not like a tight rope wire act, but it is a little nerve wracking because mistakes can be very time consuming to recover from and there is some risk of losing data.
2. Most other storage management functions (backup, replication, HSM to some degree mirroring after the mirror has been removed from the I/O channel) work with copies of data where redundancy is more or less built in. It's like working with electrical wiring when you can turn the power off. SAN management works with active I/O configurations where real data transfers might be occurring. It's like working with electrical wiring where you can't turn off the power. One little slip and BZZZZ you get shocked!
- What do they manage, wiring, storing, filing and in what combinations?
- Do they map storing and filing to each other?
- Do they report or take action?
- What do they report? (Do you need it?)
- What action do they take? (Can you trust it?)
- What's my investment in time or money to learn how to use the tool?
- What assumptions are there about the environment being managed?
- Does my environment comply with those assumptions?
- How dangerous is it if it fails and I can't make it work again?
- Can I lose data?
- Do I need to make this a part of my disaster recovery plan?
- Does it lend itself to disaster recovery?
- How can I save any configuration information that I might need to recreate my SAN with this in it?
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This was first published in February 2002