Can someone explain incremental forever to me in simple terms?
If I do an initial baseline, and it's 100MB.
Assuming a policy where we have 2 week retention on the snapvaults
So 2 weeklies, 4 nightly and 8 hourly.
Will it always be 100MB + the incrementals?
thanks
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On Nov 6, 2007 3:31 PM, Halton, Robert rhalton@tpg.com wrote:
Can someone explain incremental forever to me in simple terms? If I do an initial baseline, and it's 100MB. Assuming a policy where we have 2 week retention on the snapvaults So 2 weeklies, 4 nightly and 8 hourly. Will it always be 100MB + the incrementals? thanks
OK since no one else replied, I'll try. OSSV extends filer snapshots feature to a windows or unix filesystem. So if you understand how filer snapshots work then OSSV works the same, it is just a qtree on the filer. Let me explain, Say you are run an OSSV backup of a windows server's C drive (say \win_server1\C$) you end up with a qtree on the filer (say filer1:/vol/ossv_vol/win_server1_C) . The initial size of this qtree will be 100MB (using your number). Now lets say you setup OSSV backups to run every night and it updates 10MB of changes, then after 4 nights you will have 40MB of changes in the snapshots and about 100MB in that qtree. Now let us say you deleted 50MB of data from the source and the C drive remained around 50MB for the next 2 weeks, then when the last snapshot rolls off, your filer qtree will go back to being 50MB (your baseline). On the other hand let us say you your C drive grew to be 200MB, then the qtree also grows to be 200MB. It all depends on how the files changed on the source. If new files were added, then snapshots space is not consumed, but if files were deleted or modified, then the snapshots consume the changed blocks. Hope this makes sense. Also note that taking hourly snapshots on the filer when you only run updates every night has no impact on the filer space usage as nothing has changed during the day, so configure you snapshot schedule to match your ossv update schedules. We have been using OSSV for over 3 years now, and are happy with it, the product has matured over the years and getting better. -G
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Halton, Robert -
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