Running New-MailBoxExportRequest a second time to same PST(s)

Question

Originally asked in SBS 2011 forum yesterday - Now asking here: I recently moved a small accounting firm (18 staff) from SBS 2003 to SBS 2011. Having purchased SBS 2011 Standard over a year ago knowing end-of-support for Exchange 2003 SP3 was 8th April
2014. Today its 11th May and everything is working fairly well - except the usual suspects (WSUS) & daily network report errors (I read how to suppress those - cool - will do so soon). So, for a few dollars I have AD, Exchange 2010 SP3, wsus and this setup
is perfect for this small company. Other 2012 servers do LOB apps. SBS does Exchange. Excellent.
This was not a migration (too many things to go wrong IMHO). So I did a controlled train wreck by building a *new* Virtual Server SBS 2011 standard on one of 2 new Windows 2012 physical servers with plenty of grunt 12 TB 64 GB RAM (2 physical servers
for redundancy.) These run on the same subnet and are not domain joined - that's what I want. They are 'aloof' and I can toss VMs around at will using Hyper-V. Just thought I would describe that as it works great. I export the critical VM's monthly. Fabulous
way of backing up / disaster recovery IMHO.
As ExMerge said "are you joking!" when I tried to write out one of the partners mailboxes (7 GB lol). I had to manually export each staff member using Outlook 2010. It worked - took A WHILE. :-) But was
robust. So, over Easter I was able to import all staff PST's to Exchange 2010 SP3 on SBS 2011 - again using Outlook - logging on as each user with reboots etc.
New-MailExportRequest scripts cycling through users. OK, I can do that, and there are nice vintage 2011 PowerShell scripts for this BUT it takes TWO Hours & would wear out the HDD and probably ruin an SSD in a couple of years running this daily.
OK, my question. Having searched the internet for a couple of days I can't seem to find out what happens when I
simply run the (7 GB partners) Mailbox export to the same location the next day. Is the file overwritten? Does the script silently abort as (OMG) the PST file exists! Or, does it SYNC the PST file with all
changes (new email sent /rec / calendar updates etc.). I mean, wouldn't that be fabulous! That would be so cool as a default. Can anyone help me by explaining what a "double export" wil do to the existing PST file?
I know I can filter just todays email for an export at say 2 AM for each user. But then I need to manage little PST files all over the place - until, say, next Sunday when I do a full export again. Like incremental backups in the old days.
Sorry for the wordy post but I wanted to explain this issue. A great answer, I would venture to say, would help many 'admins' in this exact predicament.
Many thanks,
Ken
KeBugCheck(42);

Answer 1

Troy, I would expect to indeed write out two new files. The 2nd one overwriting the first one; both times, with exactly the range asked for. After all, these files are used for legal purposes. If the date range contained history items simply
because the IT admin didn't erase the earlier export, that would be poor functionality.
When I did the first export of this company, the whole process took 1 hour and 50 mins. It now just takes 40 minutes. Other factors though! The VM disk is self expanding on the Backup VM. So it would have had to grow the first time.
If I get a chance I will do your test, but I would then be looking at reporting this as a
bug to Microsoft! If the file just updated!
Not specifying a date range (with export to same PST file) should be covered in the documentation. One would expect the file to be "re-done". However watching the target file, it just sits there around 8.4 GB with just a few KB being added on the
second run through. It 'looks' like it is being updated intelligently. That is, existing items are not overwritten. With the PST file structure being fairly complicated (not just a linear file), we need someone who knows to chime in and let us know what is
happening.
I haven't tried doing just this mailbox. I will do that on one of the exported SBS 2011 sets of Hyper-V files. I will run that up on an isolated virtual private network and do some tests.
The bottom line though is because I am asking about an undocumented 'feature' :-) I was hoping someone who knew exacty what was going on could answer this. Thanks for your thoughts.
Ken
KeBugCheck(42);