[nylug-talk] Recommendations for encrypted tape drive(s)?

[Chris Knadle]

On Tuesday 04 March 2008, Luis Murillo wrote:
> Ok, I agree some of the data you provide is not something I can go up
> against at...but one thing I can say that you missed is the LTO4
> speed...the LTO4 can reach speeds of up to 240MBps on an ideal system
> but since that's not always correct, I've seen the drives work around
> 160MBps and would consider a drive that is doing less that 150MBps to
> be having performance issues...at least on SCSI :)

   Just out of curiosity I wanted to know how long it would take to back up 
the 30 TB number that Peter mentioned (with a single device):

    Rate        Time
---------------------------
   240 MB/s   36.4 hours
   160 MB/s   54.6 hours
   120 MB/s   72.8 hours


   So if an LTO4 is the fastest drive available and a company wants to do a 
full backup every 24 hours (most probably don't but some do), then it seems 
like a lot more than a single tape device is required.

> The scenario I wrote about it's completely true...I've seen it happen
> on the drives that I support.

   Yeah, at those kinds of data rates I'd believe that.  That's probably an 
interesting profile to consider concerning kernel scheduling.

   -- Chris

-- 

Chris Knadle
Chris.Knadle at coredump.us