Changing the fragment size on a PureDisk storage group

[nick_galtry]

Helle everyone,

I have a question regarding the fragment sizes for puredisk storage groups. I have an issue backing up to puredisk and I think it is down to the fragment size that is set on the storage group, my question is what effects will changing that have on the backup images already on the puredisk?

Nick

[Lee_C]

I think it's normally avoided.  The unique patterns in Puredisk are based on the fragment size, so if you change the fragment size, the patterns no longer match which essentially means your deduplication rate takes a hit.

[ElGringo]

Hello,

Could you clarify your issue ?

Regards

[AAlmroth]

Well, the recommended fragment size for storage units pointing to PureDisk disk pools is 51200. However, there are several references where a lower value is recommended (25600) when the backups fail.

/A

[AAlmroth]

I think you are referencing the segment size rather than the fragment size. For segment size, the default should be fine in the majority of implementations, and you are right, changing the value in a production environment where many backups are already stored, it may indeed have an impact on the storage use.

/A

[Lee_C]

Thanks for the correction.