I have two SSD in a machine running a fully updated openSUSE 13.1. For the first disk, I can verify that TRIM is supported by the disk's firmware, and that the kernel knows it has this capability: blackbox:~ # hdparm -I /dev/sda | grep TRIM * Data Set Management TRIM supported (limit 8 blocks) * Deterministic read ZEROs after TRIM blackbox:~ # lsblk -D /dev/sda NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO sda 0 512B 2G 1 ├─sda1 0 512B 2G 1 ├─sda2 0 512B 2G 1 ├─sda3 0 512B 2G 1 └─sda4 0 512B 2G 1 However, for the second disc, things look different: blackbox:~ # hdparm -I /dev/sde | grep TRIM * Data Set Management TRIM supported (limit 8 blocks) * Deterministic read data after TRIM blackbox:~ # lsblk -D /dev/sde NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO sde 0 512B 2G 0 ├─vgsys-kvm 0 512B 2G 0 └─vgsys-xfer 0 512B 2G 0 Why, or on what basis, does the kernel decide that the DISC-ZERO capability should be disabled for sde? What difference does it make when lsblk reports a 0 value for DISC-ZERO ? As is evident from the output above, sde is a physical device in the LVM volume group vgsys. I have set "issue_discards = 1" in the devices section of /etc/lvm/lvm.conf (but that doesn't seem to make a difference to lsblk). Suppose the ext4 file system in vgsys-xfer is mounted and fstrim is run on it, will that result in TRIM ATA commands being sent to the SSD? Regards, Olav -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org