Question

Copy data of first week in SSD disks and copy data from 2nd week to 4th week to NLSAS disks

  • 20 June 2022
  • 7 replies
  • 26 views

Userlevel 1
Badge +4

Hi,

We have data to backup with a retention period of 4 weeks. The challenge is the following:

the data within the fist week of retention period must be copied to SSD disks

the data within 2nd week to 4th week of retention must go to NLSAS disks. 

So, the goal is to not have the data of the first week retention in NLSAS disks to reduce the space.

Is there a way to reach this goal?

 

Thanks

Regards,


7 replies

Userlevel 7
Badge +17

Hi @brucquat,

This seems straight forward using a specific copy option - but it may not be all that beneficial with dedupe, and can pose a risk if something happened to your primary copy.

Here is how you do it:

Have two copies

  • Primary: 7 day retention, or even spool copy will work (keep only until copied)
  • Secondary: 4 week retention

On the properties of the secondary copy, there is a setting under copy policy called Defer Auxiliary Copy. That waits until the job is at least x days old before selecting it for copy. Set that to 7 days and it should accomplish what you want (Copy the job after 7 days and keep it for an additional 3 weeks)

https://documentation.commvault.com/11.24/expert/11496_delay_creation_of_additional_backup_copies.html

Just consider that if anything goes wrong on your primary copy, the jobs written less than 7 days ago will be unrecoverable since you wont have a second copy to restore from - and those are the jobs you’ll probably really want. 

Its important consideration if you were unfortunate enough to get hit with ransomware or some other disaster. Also keep in mind that with deduplication, you may not really be storing all that much more data in the end - most tend not to accumulate too many changes in 7 days.

 

Userlevel 1
Badge +4

Many thanks for your answer.

In fact, we will have a second storage box in a second site with the same configuration: SSD disks & NLSAS disks. And we have to apply the following scenario:

  1. Keep the data 1 week on SSD disks in the 2 storage boxes: aux copy 
  2. Keep the data from 2nd week to 4th week on NLSAS disks in the 2 storage boxes (defer copy option - thanks 😀)

Hope this is possible?

Thanks

 

Userlevel 7
Badge +23

@brucquat , I want to ensure we are on the same page:

When you say 2nd to 4th week, are you referring to when the data will be copied over to the Aux (from the Primary) or how long you will keep it?

As @Damian Andre advised, you can defer the Aux Copy by 7 days, but the downside is that if you get into a disaster scenario at any time, you’ll potentially only have data no newer than 7 days old.

Are your concerns regarding timing, or how much data you are keeping on media?  With Deduplication, the difference between 7 days on disk vs 14 (or even 21) days on disk might be far less than what you expect.

Userlevel 1
Badge +4

2nd to 4th week are referring to the retention period.

 

Explanation: we have data that have a retention period of 4 weeks. The first week of retention should go to SSD disks (on two sites for redundancy) and the data that have a retention older than 1 week, i.e. from 2nd week to 4th week, must go to NLSAS disks (on two sites also for redundancy).

Thanks. 

Userlevel 7
Badge +23

Thanks for clarifying.  Your best bet here is:

  • Primary copy to ssd: 7 days and 1 cycle retention
  • Aux Copy to NLSAS: 30 days and 1 cycle retention

Granted, you’ll end up with more data than those settings, but never LESS.

You also don’t need to worry about deferring the Aux Copy.  Let it run daily; if there’s nothing to copy. it will stop immediately.

Userlevel 1
Badge +4

Thanks for your reply but the issue is that we do not have enough space in the NLSAS disks to keep 4 weeks of data but only space to keep 3 weeks of data. That’s why we want to keep on NLSAS disks only data from 2th week of retention to 4th week.

So, in that case, I guess I need to use the feature “Defer Copy”. Correct?

Thanks for your advices.

Userlevel 7
Badge +23

Yeah, you can set the retention to Spool Copy, and defer 1 week which will have the effect of keeping Primary data for 7 days (plus the time it takes to get copied over).

That should do the trick.

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