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EMC and IBM’s Thick chunks for automagic storage tiering

TechOps Guy: Nate

If you recall not long ago IBM released some SPC-1 numbers with their automagic storage tiering technology Easy Tier. It was noted that they are using 1GB blocks of data to move between the tiers. To me that seemed like a lot.

Well EMC announced the availability of FAST v2 (aka sub volume automagic storage tiering) and they too are using 1GB blocks of data to move between tiers according to our friends at The Register.

Still seems like a lot. I was pretty happy when 3PAR said they use 128MB blocks, which is half the size of their chunklets. I thought to myself when I first heard of this sub LUN tiering that you may want a block size as small as, I don't know 8-16MB. At the time 128MB still seemed kind of big(before I had learned of IBM's 1GB size).

Just think of how much time it takes to read 1GB of data off a SATA disk (since the big target for automagic storage tiering seems to be SATA + SSD).

Anyone know what size Compellent uses for automagic storage tiering?