Discussing all things virtualization and storage in the data center.

Lets face it, we'd all love a maid!

BOOM!  Hitachi has dropped another slipper by introducing their new MAID, and from a distance she looks quite promising ;-)

Ok so I promise no more innuendos.

Basically, Hitachi have introduced to their AMS and WMS storage arrays the ability to designate RAID Groups as either “power saving” or “normal spinning”.  These new “power saving” RAID Groups can be spun down and spun up on demand although exact details of how this is accomplished are a little thin at the moment.

Now this is a technology that I think, if implemented well, is tailor made for at least two situations –

  • Backup
  • Archive


I know I know!  All the press releases have already listed these as ideal candidates but let me tell you why I will also be carrying the torch on this one…….

You will no doubt recall the recent blogsphere chatter concerning the astronomical numbers being quoted for UVM on the USP-V and the argument that the USP-V front end may not actually be able to support I/O to that much storage…..  Well I decided to take a look at some stats for an AMS1000 that was externalised behind a USP and saw some interesting numbers.  The vast majority of space on this AMS was used for email archiving and staging backups.  What I saw was that almost all of the RAID Groups were idle (zero I/O) for massive amounts of the day.  Im talking hours and hours of absolutely no activity.

Now this almost saw me pen a response to the FUD flingers but I never got around to it.However, at the time I also thought that these disks could do with being spun down when not in use.  And what do you know, a week or so later and Hitachi announce that they will support this.  Magic!

Now before I get carried away I would like to know more about how it actually works and certainly a little on how this will affect disk reliability.  

There are two things that stick in my mind re spinning disks up and down –

  1. Bill Watkins, CEO of Seagate, saying that he never powered down his home storage in response to being asked about the reliability of disk electronics when constantly powered on and off.  He should know
  2. Working for a company that went through some major UPS and power work at its primary date centre.  We had to power the data centre down every Sunday evening for several weeks.  Each week on powering our EVA storage arrays back up we, almost without fail, had at least one failed drive (FC).


With these in mind, despite all the jazzy stuff on modern hard drives (parking the heads off of the platter and improved electronics on the circuit board…….) I’m still sceptical about spinning drives down and this is not a fear I am going to overcome over night.

Like I said at the start, this looks interesting from a distance, but so do a lot of people things.  We’ll have to wait and see how it measures up on closer inspection ;-)

Nigel