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Replying to:
dpironet
1 Copper

Re: Experience / Best Practices with long time VM snaps for huge VMFS stores?

My .02 cent

>offering more flexibility to app owners when doing patches and alike.

First thing to do is to define clearly the offering here. And then use the best technology to address the offering.

Here is an idea of the offering. Thinking out loud here so I'm positively missing things

and don't forget that the journey is more important than the destination

Functionals:

1- the offering should allow a point in time (PIT) recovery state

2- the offering should allow rollback to a previous point in time (PIT) recovery state

Non-Functionals:

1- PIT recovery should be easy and quick to enable (manageability)

2- PIT recovery should should have the minimum impact on VM performance

3- In case of consolidation process, it should have the minimum impact on VM performance as well

4- PIT recovery, rollback and eventually consolidate functions should take a minimum of time to process

Let create some abbreviations:

1- TTE = Time To Enable

2- TTR = Time To Rollback

3- TTC = Time To Consolidate

Here is a table to summarise my point

VMW SnapshotVMW aware Backup
TTE Snapshot is fast

Backup takes longer

than a snapshot

TTR

Restore takes longer

than roll back of a snapshot

TTC

Variable. It depends on

the size of the delta which usually is high since it captured the many changes.

There is no consolidation per se here

and thus TTC=0. Note: snapshots are being used and consolidated during backup process. Though the goal is not the same.

PIT recovery should be

easy and quick to enable

PIT recovery should should have

the minimum impact on VM performance

Snapshot hinders VM performance

as soon it is turned on

Once the backup is done, there

is no impact on the VM performance

In case of consolidation process, it should

have the minimum impact on VM performance

Consolidation of snapshot puts a great

stress on the storage and thus hinders VM performance

There is no consolidation here

You can of course add non-functional qualities, such disk space requirement, security and cost to further add granularity to this table.

Feedback are welcome of course

Rgds,

Didier