[PVE-User] SAN and correctly propagate 'discard'...

[Marco Gaiarin]

My SAN (HP MSA 1040) have 'virtual volume' enabled, eg discard.

I've had to use directly some LUN in some VM, via iSCSI, and 'fstrim'
works as expected.


Now i'm using for some disks in my VMs, as storage of type 'LVM'.

But if i look at disk space on SAN, it is coherent with the real disk
space occupied.
While, in Proxmox, the storage volume are full or near full.

Example, VM:
***@vdmsv1:~# df -h | grep sdc
/dev/sdc1 800G 519G 282G 65% /home
/dev/sdc2 1000G 152G 848G 16% /srv

Proxmox node:
***@tessier:~# pvesm status | grep DATA0
DATA0 lvm 1 1953120256 1887436800 65683456 97.14%
***@tessier:~# pvesm list DATA0
DATA0:vm-120-disk-1 raw 1932735283200 120

and SAN report 730GB allocated.


Clearly disks of VM have 'discard' enabled, but seems that discard/trim
does not ''traverse'' all the storage chains (partition in the VM,
LV/PV/VG in proxmox node, iSCSI in the SAN).

Clearly i cannot use 'LVM Thin', because is not shared.

https://pve.proxmox.com/wiki/Storage:_LVM_Thin


Someone can give me some clue? Thanks.

[Alexandre DERUMIER]

Post by Marco Gaiarin
Clearly i cannot use 'LVM Thin', because is not shared.

[ https://pve.proxmox.com/wiki/Storage:_LVM_Thin | https://pve.proxmox.com/wiki/Storage:_LVM_Thin ]

Post by Marco Gaiarin
Someone can give me some clue? Thanks.

Indeed, LVM thin can't work with shared SAN, only on local disk.
So you can't have thin provisioning, and can't use discard.

It's just not possible, sorry.


----- Mail original -----
De: "Marco Gaiarin" <***@sv.lnf.it>
À: "proxmoxve" <pve-***@pve.proxmox.com>
Envoyé: Mardi 9 Octobre 2018 15:12:18
Objet: [PVE-User] SAN and correctly propagate 'discard'...

My SAN (HP MSA 1040) have 'virtual volume' enabled, eg discard.

I've had to use directly some LUN in some VM, via iSCSI, and 'fstrim'
works as expected.


Now i'm using for some disks in my VMs, as storage of type 'LVM'.

But if i look at disk space on SAN, it is coherent with the real disk
space occupied.
While, in Proxmox, the storage volume are full or near full.

Example, VM:
***@vdmsv1:~# df -h | grep sdc
/dev/sdc1 800G 519G 282G 65% /home
/dev/sdc2 1000G 152G 848G 16% /srv

Proxmox node:
***@tessier:~# pvesm status | grep DATA0
DATA0 lvm 1 1953120256 1887436800 65683456 97.14%
***@tessier:~# pvesm list DATA0
DATA0:vm-120-disk-1 raw 1932735283200 120

and SAN report 730GB allocated.


Clearly disks of VM have 'discard' enabled, but seems that discard/trim
does not ''traverse'' all the storage chains (partition in the VM,
LV/PV/VG in proxmox node, iSCSI in the SAN).

Clearly i cannot use 'LVM Thin', because is not shared.

https://pve.proxmox.com/wiki/Storage:_LVM_Thin


Someone can give me some clue? Thanks.
--
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Associazione ``La Nostra Famiglia'' http://www.lanostrafamiglia.it/
Polo FVG - Via della Bontà, 7 - 33078 - San Vito al Tagliamento (PN)
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Dona il 5 PER MILLE a LA NOSTRA FAMIGLIA!
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(cf 00307430132, categoria ONLUS oppure RICERCA SANITARIA)
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[Marco Gaiarin]

Mandi! Alexandre DERUMIER
In chel di` si favelave...

Post by Alexandre DERUMIER
It's just not possible, sorry.

OK. Thanks.

[Marco Gaiarin]

Post by Marco Gaiarin
Someone can give me some clue? Thanks.

Only for the sake of google: trim correctly propagate between virtual
disks to the SAN.

After rebooting the SAN controllers(s), all ''numbers'' go OK.


Sorry. Thanks.