Mixing flash and spinning disk.

[lolbebis]

Hi,
We have a flash scale out repo in Veeam to be able to run reverse incremental backups.
The idea was to tier the older incrementals to S3 but our object storage didnt want to play.

What would happen if we added spinning the disk to the scale out repo and only stored incrementals on spinning disk.
And store the full backup on flash.
Would most of the I/O go to the flash disk?

I found this information:
"
– 1° I/O to read the bit in the .vbk file that needs to be replaced
– 2° I/O to substitute that bit with the new one extracted from the VM disk
– 3° I/O to write the old bit into the newly created .vrb file

Also, since substitutions comes from different and unpredictable blocks of the production VM, we will have random access to the saved data, and this will even worse the performances of backups if compared to the sequential writes done during a forward incremental.
The real value can be 4x of the original I/O."

If that is correct then 75% of all I/O would go to the flash disk?

Found it here:
https://www.virtualtothecore.com/veeam- ... torage-io/

[foggy]

Hi Mattias, your understanding is correct, though it would be 66% of the repository I/O for flash disk (2 I/O operations vs one for spinning disk). Thanks!