Betting the 3rd party provider performs multiyear archive service.
IRS retains current “six month” history.
IRS, on a rolling basis, sends the “seventh” month out to an Iron Mountain or some service for long term Archiving
If it’s the same thing that the SEC currently requires for stockbrokers, then absolutely yes. Anything really old not immediately accessible on their servers gets burned to disc and saved indefinitely.
Same should now be required for all branches of government.
Betting the 3rd party provider performs multiyear archive service.
IRS retains current “six month” history.
IRS, on a rolling basis, sends the “seventh” month out to an Iron Mountain or some service for long term Archiving
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Although they are not using IBM’s DFHSM for archiving e:mails the scheme would be similar with multiple levels of backup , each more distant and cheaper than the prior ... first level is on an online server , uncompressed and instantly retrievable ,, covers perhaps data that is less than 1 year old. ,, second level would be compressed on a server , slower ,, might take a few minutes ... third level would be archived to tape backup for data more than a few years old ,, backup tapes , if not needed for compliance , would be periodically recycled with copies of data that has been deleted off of online servers deleted off of backup tapes after a period of time (5 years , 7 years...) has passed ,, the “deleted” data is still there of course until a tape recycle event where the “gas” is compressed out of the tapes.
In 2014 when I can buy a 1TB drive for well under $100 there is no real reason for deleting anything. I ran a datacenter back in the late 1980’s early 1990’s with a total of 3tb of dasd storage and 7 LARGE mainframe computers (all 308x and 309x series) ,,, it was a HUGE datacenter ... today a single , under $1000 server can archive that entire datacenter 2x over with a raid that provides hot-swap backup and data continuity.