Monday, February 17, 2014

End of a Personal Era




waiting to be disposed

This past week I uninstalled a lot of DDN 9550s.  These were the workhorse storage platforms we used for our global filesystem for years.  Too long, in fact, but budgets are what budgets are and storage normally gets the short end of the stick at HPC centers.  However, the 9550s were really, really stable.  They used 300 GB fiber channel drives to come to a total of somewhere around 720 terabytes of disk.  My loss rate for them was less than 10% - I believe somewhere around 2%, actually - of the newer 9900s with the 1 TB SATA drives.


my row of 9900s

The DDN 9900s are fine, really.  I manage 11 of them with those 1 TB SATA drives (see below).  This comes to about 3.3 petabytes worth of our global filesytems.  Interestingly, the problems which I have are not seen by my compatriots who work with the SAS drives.  However, their SAS drives are 300 GB, so if I were to substitute mine with those drives, while more reliable, they would give a capacity hit down to less than one petabyte. Those are not the newest systems, obviously, but they are useful.  Even if they give me most of my headaches.

my row of sfa12kes, only first 4 racks are mine

These days the new toys are my sfa12kes.  These are embedded servers with virtual machines which run on the disk controllers.  They have been remarkably stable and nonfussy.  I have my issues with them still (specifically their software stack (dude, rolling upgrades, really! need! this!)), but DDN is making progress on its development.  The five 12kes use 3 TB near-line SAS drives which gives me 5.1 petabytes of spinning disk (and I'd like to fill them out to their full capacity for 6 PB, but, again, a budgetary issue.  We spec'ed them for a specific bandwidth/capacity ratio.  Unlike the previous two types of DDN pictures here, not only are the 12kes with embedded servers, they have some spiffy FDR infiniband cards.  Half are tasked to be 10 Gig ethernet, a quarter are FDR IB and the rest of QDR IB (legacy systems).  Plans are afoot to move everything onto FDR IB and use ethernet gateways for the legacy systems.  We have to get rid of the QDR systems though.

  seismic isolation planks where the 9550s were
 
At any rate, this is an end of a personal era at NERSC.  No more FC drives for me.   And a glimpse of some of what I do at the dayjob.

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