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April 1st, 2014 21:00

Concurrent sessions / backup !!

Hello everybody !

I have some confusions about the concurrent backups or jobs per storage or utlity nodes for Avamar 7 & 6 Virtual or physical appliances , I reviewed all avmar documentation , but somehow not clear for me:

Is there difference between Concurrent connections and concurrent backups for Avamar
utility or storage or Grid ?

What is Maximum Concurrent connections per storage node and where to configure it ?

What is Maximum Concurrent connections per utility node , and where to configure it ?

What is Maximum Concurrent backup and restore jobs handled same time per utility node
and OR storage node /or Grid ?

from where I can control the above concurrent sessions ?

I checked#

I can see this config file for AVE7 & 6 with little changes for 7:


but I can not see any correpsonding values for the concurrent sessions as values differes from Avamar documentations.

ANy explanations ?

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135 Posts

April 2nd, 2014 04:00

I can't answer all of your questions, but here's my two cents:

What is Maximum Concurrent connections per storage node and where to configure it ?

Avamar 6.1: 27 connections per storage node

Avamar 7: 72 connections per storage node (wow, I might have to consider upgrading soon! )

Total concurrent backups for Avamar 6.1 is (27 x N) - 1

Where N is the number of storage nodes. I don't know if the utility node counts for the number of sessions. 1 session is always held free for restores. I don't think you can configure this limit yourself.

This applies to a physical grid. A single-node Avamar is a storage/utility node in one, so the 27 or 72 limit applies to that, I think. Not sure about virtual instances. Try googling for "Avamar concurrent backups", that's how I found out some of this information.



16 Posts

April 3rd, 2014 20:00

Hello Steve

Thanks a lot for your time answering me , I already did a lot of googling before to post here, with no clear understanding , I failed in Avamar Exam only for 3% , but I am not so down so far

so I am trying to catch what I missunderstand , the above you mentioned is already documented , but my questions reflects my confusion about the values I need to know.

let me share with you something from one of EMC online training , I can not remember the course name#


Avamar 7.0 supports concurrent backup and restore operations. This means that multiple

backup and restore jobs can run at the same time.  Avamar 7.0 allows up to six concurrent

backup/restore operations to execute on a single host.  The six concurrent backups are

limited to the Avamar Administrator GUI and application. For example, on a host running

DB2 and Lotus, the following GUI-initiated operation can run concurrently: six Lotus backups,

four DB2 backups, and two DB2 restores (plus any number or CLI-initiated backups/restores). 


so the single client can send up to 6 per host , so they say per application 6 ones , so how comes ? is it 12 per host "or could be more using CLI" based on different processes / application type or Avamar GUI ?

on the another hand , the online Assessment test exam for Avamar asks for#

(( how many simultaneous client connections are supported by an EMC Avamar Virtual Edition server))

8 , 27 , 35 or 72 ,, none of those values are listed in the:


configueration file !!

the only closer one is:

"completed jobs retention hours "72" ,,  parameter , which make no sense

and the closer value in meaning is#

max concurrent jobs="500"

and look to the below image, if Avamar proxy can handle 8 Backups maximum , and the Avamar node can deal with up to 48 which total of 384 concurrent Backups , so it exceed the 72 already !!!


Are you confused now Steve



December 1st, 2015 05:00

There should be no confusion as the limit for no. of concurrent backup depends on no. of nodes configured in an avamar server. If sufficient nodes are deployed then avamar proxy clients can support 384 concurrent backups at max, the only condition is that there should be atleast 6 storage configured of avamar version 7 server.

July 19th, 2016 09:00


do you have some "VMware Maximus like" limits matrix for EMC Avamar v7.2 ?

I have a problem at my customer enviroment that we can only restore 1 concurrent single/same VM (Image, disk or FLR) at a same time. Is this some hard (by design) limit or can be changed somewhere?

And we need to concurrent restore same VM more than 1 at a same time (for example in the same time do a image restore and FLR restore).

best regards


1.2K Posts

July 19th, 2016 13:00

Just to clarify, which one of the following:

"I can only restore any single VM at a time. I cannot do a VM Image restore of VM #1 and VM #2 at the same time, I must wait for VM #1 to finish before VM #2 will start"


"I can only do a VM image of any single VM at a given time. I must wait for the image restore from VM #1 to finish before I can do an FLR restore from that same VM, VM #1"?

July 20th, 2016 00:00

thanks for response Karl,

I mean only about simultaneous restore same VM, I can only run 1 restore of same VM at a same time, next restore/restores of this VM are in Waiing state until first restore will finish.

1.2K Posts

July 20th, 2016 07:00

To me, it seems like that's behaving as-expected.  Avamar basically handles only one backup event per client.  Even though backup and restores of VMs are handled by the proxies, each proxy can still only run one backup (or restore) of a VM at time.

Support might be able to suggest a few options that might work.  If you haven't done so, you should open an SR to that effect.

Let us know if that helps!


73 Posts

July 20th, 2016 14:00

Depending on how your environment is configured you might have two other options.  If you have more than one Avamar grid and you are using policy based replication you should be able to do 2 restores of a client at the same time.  Do the VM restore from one grid and FLR from the other.

Also you could do a both a VM backup and install an agent and backup files like a traditional physical server.  If your going to do a lot of file restores VM FLR has a soft limit of 5,000 file or folders.  In general I personally rely on traditional agent based backups for most file servers because its easier to restore single files.

July 21st, 2016 03:00

Karl, Ryan_Johnson,

Thanks for reply mates.

So because of that fact that there is some limits of restore tasks of same VM (client) at a same time I looking for such document where are the limits, because of what and how/if they may be extended.

I will try option to restore same VM (client) via different proxies and give you the results here soon.

Also option to use second Avamar (replicated) looks quite nice, I'm not sure how it will work over looong WAN link (about 3000km) but if it possible to do such long distance restore (Avamar and DD replication working over it).

Idea to use standard agent based backup is also interesting, I need some time to test it in lab environment, but maybe it's also some workaround.

But anybody know the real limits of simultaneous restore (of single VM/client) of Avamar v7.2 ...?

thanks for help mates!!

August 19th, 2016 07:00

FYI - here is an article which may be a useful reference

  • KB 335770 - How many simultaneous client sessions can be made to the Avamar server?

1.2K Posts

August 22nd, 2016 07:00

The KB that Nicholas linked pointed out another detail:

  • Backup sessions initiated by avtar commands bypass the MCS and will therefore not obey the limitations defined above.

I forgot all about this.  Have you tried running avtar restore commands for your restore?  I'll bet you can run your VM restores in parallel, since MCS is doing the same thing under the covers - I think it will ignore the client limits and allow more than one restore to run at the same time. 

In simple terms, build out a VMimage restore command on the CLI for each disk you wish to restore, then build out an FLR restore command for the FLR restore.  Kick off both restores in short order and see if they can run together.  I'm betting they will.

Let us know if that helps!

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