We are happily using Virtual Synthetic Full backups for huge file servers where we need to do daily backups (with weekly fulls) / 1 month retention.
It’s very useful, because we don’t need to (re-)read eg. the ~1T drive every week, DD+NW is doing the trick, so only incremental backups are executed on the client every day.
The problem arises when we need to keep monthly full backups with 6 years retention..
We have 2 savegroups (nw8):
daily backups: 1 month retention, schedule: synth full on saturday, incremental every other days, skip on 1st saturday every month
monthly backup: 6 years retention, schedule: synth full on 1st saturday every month, skip rest of the month
The problem: when we do the monthly (6y) backup, the 1st step is an incremental backup – this is how virtual synth. full works – however this saveset is stored with 6y retention, which prevents the expiration of the backups made on the previous week.
# mminfo -ot -q “client=…,name=G:,savetime>01/10/2018,savetime<02/05/2018” -r “savetime(17),ssretent,ssflags,sumsize,level,name”
date time retent ssflags size lvl name
01/27/2018 18:23 02/27/2018 vF 1162 GB full G:
01/28/2018 18:23 02/28/2018 vF 1779 MB incr G:
01/29/2018 18:23 02/28/2018 vF 54 GB incr G:
01/30/2018 18:24 02/28/2018 vF 81 GB incr G:
01/31/2018 18:23 02/28/2018 vF 65 GB incr G:
02/01/2018 18:24 03/01/2018 vF 62 GB incr G:
02/02/2018 18:23 03/02/2018 vF 71 GB incr G:
02/03/2018 18:21 02/03/2024 vF 78 GB incr G:
02/03/2018 18:21 02/03/2024 vF 1164 GB full G:
I’ve open an RFE to ask EMC to remove the incr backup if the synthesis was successfull (I think we don’t need it, the data is already stored within the synthetized full).
A good workaround is to make a regular full for the long retention backup, but it’s not nice.
Do you have any other ideas?