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June 13th, 2018 00:00
Virtual Synthetic Full vs. 1 month _and_ 6 years retention
Hello,
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?
bingo.1
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June 13th, 2018 07:00
I see 2 solutions:
1. you could write a script which adjusts the retention date of the INCR save set, like:
mminfo -q "client=...,level=incr,name=G:\,savetime>01/10/2018,savetime<02/05/2018" -r "ssid,cloneid" -xc/ > ssid_file
'delete the first line (header) of the file'
'prepare a script file for each entry that adjusts the retention time
nsrmm -y -e "mm/dd/yyyy" -S "ssid/cloneid" '
'run that file'
Unfortunately you cannot make nsrmm to read a ssid file
2. you could write a script which deletes the incremental adjusts the retention date of the INCR save set, like:
mminfo -q "client=...,level=incr,name=G:\,savetime>01/10/2018,savetime<02/05/2018" -r "ssid,cloneid" -xc/ > ssid_file
'delete the first line (header) of the file'
'prepare a script file for each entry that deletes the last incremental save set'
nsrmm -y -d -S "ssid/cloneid" '
'run that file'
Again you cannot make nsrmm to read a ssid file
oldhercules
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June 13th, 2018 12:00
Thanks.
What do you think, is there any reason for networker to keep the incremental backup which was made on the day of the full backup?
bingo.1
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June 13th, 2018 13:00
No - because the data is already part of the synthetic ful SS.
bingo.1
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June 15th, 2018 23:00
I just checked an interesting point.
The command
nsrmm -y -e "mm/dd/yyyy" -S "ssid/cloneid"
according to the Command Line Reference, refers to a specific retention date.
But the Command Line Reference also states that the format follows the nsr_getdate format.
This implies that relative time periods are possible as well as absolute dates. Yes - it works indeed.
So instead of specifying
nsrmm -y -e "01/16/2019" -S "ssid/cloneid"
you could also use
nsrmm -y -e "+7months" -S "ssid/cloneid"
Of course the period starts from the current date.
oldhercules
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June 18th, 2018 23:00
As I know this is quite old feature.. the interesting thing is that cloning with NW9 is using that for clone retention if you do not set it.
With NW8 when you had a saveset with eg. savetime 01.01 (dd/mm), 1 month retention (till 01.02) then if you cloned the saveset (any time without specifying retention while cloning) the clone ss got 01.02. With NW9 now +1 month is added to the current cloning date.. this is sick.
bingo.1
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June 19th, 2018 01:00
Quite a bunch of (tiny) issues have beein improved over the years ... but have not been updated in the docs.
Unfortunately you only discver them if you permanently 'play' with NW.