Advice: 3par/StoreOnce and a vm with Multiple Disks

[stb74]

We are using HPE Converged system with 3Par and StoreOnce. When backing up a vm with multiple vmdk's attached there is only one backup stream running. If we have 10 vm's with a single disk there will be multiple streams doing the backup. The single vm will only get around 200MB backup processing where as the multiple vm's will get around 200 each.

[foggy]

All VM disks are written to the same file, one file requires a single stream. When per-VM setting is enabled for repository (like in your case, I believe), this allows for multiple write streams to the storage for different VMs, since every VM has it's own backup chain. However, in case per-VM is disabled, all VMs in the job are stored in one chain and written through a single stream.

[stb74]

I do have per-VM setting enabled.

Does Veeam make per VM backup file instead of per VMDK backup file as the backup target is StoreOnce Catalyst.
We have discovered this creates several issues, such as slow restore and sometime slow backup and slow virtual synthetic full backup as well
for VM with multiple disks. This can also make restoration of VMs with multiple VMDKs slow.

Just for testing, I have created a VM with 5 VMDKs and then 5 fake new VMs without any disk, finally I have assigned the disks of the 5-VMDK VM to my new 5 VMs.
At this point I have made 2 backup tests
1) job with the 5-VMDK VM --> Throughput 250MB/s (each VMDK ran with 50MB/s in parallel, one stream running to the StoreOnce).
2) job with 5 VMs ( each one associated to on VMDK of the 5-VMDK VM) --> throughput 1000MB/s

[jazzoberoi]

Can this behaviour be optimised so if we have one VM with multiple VHDX files, they get one stream per VHDX ?

[foggy]

Does Veeam make per VM backup file instead of per VMDK backup file as the backup target is StoreOnce Catalyst.

It is per-VM in the sense where each VM data is stored in a separated backup chain, but all VM disks are stored in a single restore point.

We have discovered this creates several issues, such as slow restore and sometime slow backup and slow virtual synthetic full backup as well
for VM with multiple disks. This can also make restoration of VMs with multiple VMDKs slow.

We are aware of performance impact this might have in different scenarios and have plans for optimizations (both in terms of backup and restore - now, when StoreOnce has allowed shared read, parallel disk restore is also possible).