HP D2D D2D NAS Integration with CommVault (EH985-90934, March 2011) - Page 32

Other considerations, Ensuring you do not exceed D2D maximum open file limits

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5 Other considerations Ensuring you do not exceed D2D maximum open file limits The HP D2D NAS share has strict allocations for the number of open files it can have open at any given time (See Appendix B). Should these limits be exceeded a lost connection may occur, causing the backup to fail and there will be an entry in the D2D Event log. Possible causes for this situation might be: • Too many simultaneous backup streams going to a given D2D NAS share: In this case the number of writers being used or the number of backup jobs scheduled at the same time should be reduced. • CommVault Data Aging process: This is selectable as an attribute of the CommVault Storage Policy and frees up space after the retention period has been exceeded. It is recommended to schedule it to run outside of the backup window. See below for more information. • CommVault GridStore technology: This is an additional licensable feature that allows the automatic failover of backups to an alternative path or for a device to be accessed by a separate media agent should the primary path become inaccessible. It is possible that a race condition can occur as follows: 1. We exceed the number of open files to a D2D NAS share, causing a "lost connection" as seen from CommVault. 2. This triggers the Grid Store technology to re-send the backups on a round robin basis to another device that already has a high load. 3. We then exceed the open file limits on that D2D NAS store which, in turn, gives lost connection and so it continues. See below for more information. Data Aging Scheduling in CommVault Simpana 9.0 Data Aging is a process in CommVault Simpana 9 that frees up space once a backup device data retention period has expired. This process needs to be managed because data aging involves data overwrites which in turn generates housekeeping. If a housekeeping blackout window is set, this should limit the impact of the data aging process. If a housekeeping blackout window is NOT set, schedule the data aging process to run outside of the backup windows as shown below: 32 Other considerations

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5 Other considerations
Ensuring you do not exceed D2D maximum open file limits
The HP D2D NAS share has strict allocations for the number of open files it can have open at any
given time (See Appendix B).
Should these limits be exceeded a lost connection may occur, causing the backup to fail and there
will be an entry in the D2D Event log. Possible causes for this situation might be:
•
Too many simultaneous backup streams going to a given D2D NAS share:
In this case the
number of writers being used or the number of backup jobs scheduled at the same time should
be reduced.
•
CommVault Data Aging process:
This is selectable as an attribute of the CommVault Storage
Policy and frees up space after the retention period has been exceeded. It is recommended
to schedule it to run outside of the backup window. See below for more information.
•
CommVault GridStore technology:
This is an additional licensable feature that allows the
automatic failover of backups to an alternative path or for a device to be accessed by a
separate media agent should the primary path become inaccessible. It is possible that a race
condition can occur as follows:
1.
We exceed the number of open files to a D2D NAS share, causing a “lost connection”
as seen from CommVault.
2.
This triggers the Grid Store technology to re-send the backups on a round robin basis to
another device that already has a high load.
3.
We then exceed the open file limits on that D2D NAS store which, in turn, gives lost
connection and so it continues.
See below for more information.
Data Aging Scheduling in CommVault Simpana 9.0
Data Aging is a process in CommVault Simpana 9 that frees up space once a backup device data
retention period has expired. This process needs to be managed because data aging involves
data overwrites which in turn generates housekeeping.
If a housekeeping blackout window is set, this should limit the impact of the data aging process.
If a housekeeping blackout window is NOT set, schedule the data aging process to run outside of
the backup windows as shown below:
32
Other considerations