EMC World – Day 4 – VNX: Skew & Data Placement

Hitachi Ultrastar SSD400S SSD FamilyThe last breakout session I attended at EMC World 2013 was titled “Leveraging SSD: Designing for FAST Cache & FAST VP on Unified Storage”. By far one of the best breakout sessions of the week for me: technical and I can apply it in the field on pretty much a daily basis!

If you’ve got SSD drives in a VNX you can use it in two ways: as FAST Cache or as an extreme performance tier in your storage pools (FAST VP). Either of these implementations has advantages and disadvantages and they can also be used concurrently (i.e. use FAST Cache AND FAST VP). It depends on what you want to do…

But let’s start at the beginning: first you need to figure out your skew! What?!

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CLARiiON CX3 vault drive failure

Yesterday I received a call about a drive failure in a CLARiiON CX3-80 storage array. Since every system has at least a couple of hot spares configured, usually this does not pose a problem. But this drive failure happened on drive position 0_0_0: a vault drive failure.

The vault drives host (amongst others) the operating system and configuration of the storage array. They are also used to destage the write cache in case of an event that might threaten data integrity.

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