equallogic

It looks like Dell/Equallogic won the mid-size storage array of the year. I am currently working with a customer to get rid of one. My guess on why it has such a large install base in this industry is the fact that it is the standard of one of the large IT support firms that do support in my industry.

It does work. It can be fairly slow and uses RAID-50. Yes, RAID-50. Each unit itself can only have 14 disks and dual controllers. It is pure iSCSI. If you want to add disk, you add a unit and create a group. The group is basically a multitude of units in which a pool of storage is created. Hosts connect to the group IP and that forwards you to the correct unit to get your data.

It is basically the same thing the big guys are trying to do with storage virtualization. EMC and Netapp have been doing similar stuff on a larger scale. The idea is cool. You pop one of these and add it to the group and it auto-configures its RAID groups, IP info, disks, access, etc. Pretty neat.

It is a slow performer though and that is why we are getting rid of it, on top of the fact that the way it grows vertically is something we dont desire. I do suggest reading a bit about RAID-50 though.

Storage Virtualization

From Wiki: Storage virtualization refers to the process of abstracting logical storage from physical storage. The term is today used to describe this abstraction at any layer in the storage software and hardware stack.

I have done evaluations on EMC Invista (block virtualization) and the cost is very prohibitive to the organization I was working with. We had the Cisco 9506 switches necessary for the SSM module to snap in storage virtualization, but the SSM module itself was 250K or so with the software for both SANs.

At that time the only thing Invista was really good at was storage migrations. Yes, that is a main feature of storage virtualizations, but I wanted some ILM. I want this thing to understand the data and auto-move based on rules. I believe the latest version has some basic capabilities to do this, but I can do storage migrations in the background using other tools, even cheesy ones like Open Migrator.

By the way Open Migrator works very well for WIndows hosts. I would just do it yourself. Dont pay EMC to do the services as the product is a cake walk. Basically you create a pair with the targe LUN, it syncs without any affect to the host, when it is done you reboot and it switches over. It does require a couple reboots though depending on if the driver is needed.

I would welcome conversation on any real examples of Invista. I know that HDS and IBM have been doing their version of storage virtualization and have real customers. EMC, not so much.