Storage optimization, ashift 9 vs 12

[Chris123]

I have a mirrored pool, two ST4000DM000 (Seagate 4TB), that will contain backup of zvols (only). I'm trying to optimize for storage space (and not so much performance). Experimenting with ashift=9 shows a 25-30% space improvement over ashift=12. Are the any red flags using ashift=9 on a 4k-drive mirror pool besides the performance reduction?

Thanks,
Chris

 

[jgreco]

Not really, not that I can think of. My impression of the arguments about this sort of thing in the past is that with compression, ashift=12 ends up working fine in many cases, and would tend to be less stressy on the system as well.

 

[Chris123]

Ok. I'll give it a try then. Thank you for the reply.