DELL PERC H965i logicals blocks size 512 failed

[Eric]

Hi, On a DELL R770, it appears that the DELL PERC H965i card hard-codes the block size to 4096 bytes when creating a RAID, regardless of whether ‘512, 4096 or both’ is selected.
The result is that you cannot create a VDI on the SR created with the RAID because the logical and physical block size is 4096.
[]# cat /sys/class/block/sda/queue/physical_block_size
4096
[]# cat /sys/class/block/sda/queue/logical_block_size
4096

I have opened a ticket with DELL, but have you already encountered and resolved this issue, which seems to date back several months?

[Eric]

Réponse du support DELL :

Le comportement est normal et lié à la conception du PERC H965i :
️ Le RAID matériel du H965i publie uniquement des volumes en 4 K, même si les disques sont 512e.

Il n’y a pas de moyen de forcer un VD en 512 bytes sur ce contrôleur.

Voir la notre en haut de la page :
https://www.dell.com/support/manuals/fr-fr/perc-h965i-mx/perc12/virtual-disk-features?guid=guid-cd78f88c-5747-412f-8aae-6b26dd7ce2fd&lang=en-us

Apparemment on peut créer des VDI en mode type raw avec le SR créé avec le VD 4k.
Quels sont les différences entre VDI VHD et RAW à l'utilisation ?

[olivierlambert]

Hi!

See https://docs.xcp-ng.org/releases/release-8-3/#4k-native-disks and https://docs.xcp-ng.org/storage/#largeblock-sr

Note that qcow2 format is supporting 4k natively, and it's in release candidate stage, maybe the right approach in a near future