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NetWorker and the Y2038 Problem

Posted by Preston on 2009-01-25

Having spent what seemed like much of 1999 coordinating the system administration efforts of a major Y2K project for an engineering company, I have fundamental problems with the plethora of journalists that claimed the overall limited number of Y2K issues experienced meant it was never a problem and was thus a waste of money. (I invite such journalists to stop filling their cars with fuel, since they don’t run out of fuel after they’re filled – it’s a similar logic.)

Thus I’m also aware of the difficulties posed by 2038 – that’s the point where we reach numbers that can no longer be expressed as seconds since 1 January 1970 in a 32-bit integer.

Interestingly NetWorker doesn’t seem to technically have the Y2038 problem, since that problem is meant to manifest in early 2038, but NetWorker allows retention and browse periods specified for its savesets up to and including 31 December 2038 23:59:59.

However, NetWorker does still appear to have a pseudo-2038 issue in that it currently doesn’t allow you to specify a browse or retention period beyond 31 December 2038 23:59:59.

For instance:

[root@nox ~]# save -qb Yearly -e "12/31/2038 23:59:59" /etc/sysconfig
save: /etc/sysconfig  219 KB 00:00:01    115 files
[root@nox ~]# save -qb Yearly -e "01/01/2039 00:00:01" /etc/sysconfig
6890:(pid 18236): invalid expiration time: 01/01/2039 00:00:01

I have 2 theories for this – neither of which I’m willing to bet on without being an EMC engineer who has access to the source code. Either NetWorker doesn’t really store dates as of 1 January 1970 (instead storing from some time later in January 1970) or it’s only partly surpassed the 32-bit barrier for date/time representation – e.g., the back-end supports it but the front-end doesn’t, or the back-end doesn’t support it and the front-end does, but knows the back-end doesn’t and therefore blocks the request.

Either way, it’s something that companies have to be aware of.

Where does that leave you?
Well, being unable to set a browse/retention period beyond 2038 for now is hardly an insurmountable issue, nor is it an issue that should, for instance, discount NetWorker from active consideration at a site.

Instead, it suggests that for long term data retention requirements – e.g., requirements exceeding 30 years (such as government archives, medical records that must be kept for the life of patients, academic records that must kept for the life of the student, etc.) need to be stored with well established and documented policies in place for extending that data retention as appropriate for backups.

Such policies aren’t difficult to enact. After all, data which is to be stored on tape for even 5+ years really should have policies to deal with recall and testing, and it goes without saying that data which is to be kept on tape for 30 years will most certainly need to be recalled for migration at some point during its lifetime. (Indeed, one could easily argue it would need to be recalled for migration to new media types at least 3 times alone.)

So, until NetWorker fully supports post-2038 dates, I’d recommend that companies with long-term data retention requirements document, and establish extensions to their policies as follows:

  • Technical policies:
    • All backups that should be kept beyond 2038 should be appropriately tagged – whether that simply be by being within a particular pool, or just by having a data expiration period higher than the year 2037 will depend on the individual company requirements.
    • Each new release of NetWorker should be tested, or researched to confirm whether it supports post-2038 dates.
    • At any point that post-2038 dates are supported, the savesets to be kept longer than 2038 should be extended.
  • Human resource policies:
    • New employee kit for system/backup administrators must make note of this requirement as an ongoing part of the job description of those who are responsible for data retention.
    • New employee kit for managers responsible for IT must make note of this requirement as part of an ongoing part of their job description.
    • HR policy guides should clearly state that these policies and requirements must be maintained, and be audited for periodically.

With such policies in place, being unable to set a browse/retention period currently beyond 2038 should be little cause for concern.


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