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How old is your media?

Posted by Preston on 2009-01-25

There are several components to determining media ‘age’. These are:

  • Usage count – the more times a tape is used, the more wear that tape experiences.
  • Operating and storage environment – temperature and humidity play an important role.
  • Elapsed time from manufacture date.

Keeping track of operating/storage temperature and humidity is a physical process requiring specific procedures and rules – e.g., ensuring that media is transported between the off-site vault and the on-site storage in appropriately protective pouches or boxes. The amount of protection will depend on the overall environment – in many cities this will require little protection, but in areas around the tropics, for instance, humidity issues can strike media moving over distances as small as fifty metres.

Luckily, NetWorker allows you to track:

  • How many times a volume has been labelled/recycled.
  • When a volume was first labelled.
  • How many times a volume has been mounted.

This is as simple as the following command:

# mminfo -q “family=tape” -r volume,olabel,labeled,mounts,recycled

For example, on a lab server I get the following output:

[root@nox ~]# mminfo -q "family=tape" -r volume,olabel,labeled,mounts,recycled
 volume        orig lbl  labeled mounts rcyc
800840D       11/07/2006 07/05/2008  97  30
800841D       11/08/2006 07/16/2008 115  35
800842D       04/05/2007 06/06/2008  44   6
800843D       03/29/2008 05/30/2008  14   3
800844D       03/29/2008 05/29/2008  13   4
800845D       11/08/2006 06/09/2008 122  40

This is a little messy – one way to clean it up is to force the inclusion of the timestamp for each of olabel and labeled, which makes the output somewhat easier to read:

[root@nox ~]# mminfo -q "family=tape" -r "volume,olabel(25),labeled(25),mounts,recycled"
 volume                orig lbl                  labeled         mounts rcyc
800840D           11/07/2006 12:19:46 PM   07/05/2008 11:41:01 AM    97  30
800841D           11/08/2006 02:30:07 PM   07/16/2008 01:24:55 AM   115  35
800842D           04/05/2007 09:23:31 AM   06/06/2008 03:46:06 PM    44   6
800843D           03/29/2008 04:49:28 PM   05/30/2008 12:42:32 PM    14   3
800844D           03/29/2008 10:08:52 AM   05/29/2008 11:26:32 AM    13   4
800845D           11/08/2006 02:42:40 PM   06/09/2008 07:13:35 AM   122  40

Obviously, you can also run this command with the option “-xml” (or “-xm”) to output in XML format – I prefer to use “-xml” rather than “-xm” simply because it serves as a reminder of what the output is going to be, or in CSV format – “-xc,”. CSV format would look like the following:

[root@nox ~]# mminfo -q "family=tape" -r "volume,olabel(25),labeled(25),mounts,recycled" 
-xc,
volume,orig-label,labeled,mounts,recycled
800840D,11/07/2006 12:19:46 PM,07/05/2008 11:41:01 AM,97,30
800841D,11/08/2006 02:30:07 PM,07/16/2008 01:24:55 AM,115,35
800842D,04/05/2007 09:23:31 AM,06/06/2008 03:46:06 PM,44,6
800843D,03/29/2008 04:49:28 PM,05/30/2008 12:42:32 PM,14,3
800844D,03/29/2008 10:08:52 AM,05/29/2008 11:26:32 AM,13,4
800845D,11/08/2006 02:42:40 PM,06/09/2008 07:13:35 AM,122,40

The amount of usage or age you’ll tolerate on your media before replacing is dependent on the following factors:

  • Vendor stated usage factors
  • Your level of tolerance to age of media
  • Any failures that may occur during periodic testing
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