When a VM sends a discard/trim command, is it sent to the SSD, LVM does not block the command?
Hi, yes it's working with lvm (lvm thin only) >>Or is it useless, because mdadm handles discard/trim in his own way? The trim command need to be send by the guest os. on linux guest : /etc/fstab discard option on mounpoint, or run fstrim command in cron, on windows: it's a periodic schedule task (in "optimize disk" tool) ----- Mail original ----- De: "Frédéric Massot" <frede...@juliana-multimedia.com> À: "proxmoxve" <pve-user@pve.proxmox.com> Envoyé: Jeudi 12 Décembre 2019 17:00:47 Objet: [PVE-User] Discard transmission between VM / LVM / mdadm layers ? Hi, I have a question about the discard/trim transmission between the VM / LVM / mdadm layers up to the SSD. I have a server with four disks mounted in a RAID 10 array with mdadm. On this RAID 10 array, there is a volume group with LVM, which contains multiple logical volumes for the hypervisor and VMs. fstrim is periodically launched on the hypervisor and VMs. I know that : - A VM can pass discard/trim commands to the lower layer if it uses a "Virtio SCSI" controller. - LVM (since 2.02.85 with issue_discards enabled) can pass discard/trim to the lower layer during remove or reduce operations of a logical volume. - mdadm supports discard/trim since kernel 3.7. When a VM sends a discard/trim command, is it sent to the SSD, LVM does not block the command? Or is it useless, because mdadm handles discard/trim in his own way? Regards. -- ============================================== | FRÉDÉRIC MASSOT | | http://www.juliana-multimedia.com | | mailto:frede...@juliana-multimedia.com | | +33.(0)2.97.54.77.94 +33.(0)6.67.19.95.69 | ===========================Debian=GNU/Linux=== _______________________________________________ pve-user mailing list pve-user@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user _______________________________________________ pve-user mailing list pve-user@pve.proxmox.com https://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-user