[linux-lvm] discard with luks and the FS itself

[lejeczek]

hi everyone

I realize question does not pertain LVM directly but knowing
that on the list wonder around some very crypt-savvy
guys&gals I thought I'd ask:

Does one have to flag mounts with discard for both crypttab
and fstab in order for TRIM to be in effect?
Or just one? Just crypttab?

I've searched but failed to find an ultimate answer.
b.w.
L.

[Sven Eschenberg]

Depends on your storage stack configuration, but the answer is mostly yes:
cryptsetup has discard disabled by default, for very good reasons.
filesystems vary, so you'd have to check on your particular filesystem
documentation.

That's probably why you cannot find the ultimate answer - there's none.

Regards

-Sven

Post by lejeczek
hi everyone
I realize question does not pertain LVM directly but knowing that on the
Does one have to flag mounts with discard for both crypttab and fstab in
order for TRIM to be in effect?
Or just one? Just crypttab?
I've searched but failed to find an ultimate answer.
b.w.
L.
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linux-lvm mailing list
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

[lejeczek]

Post by Sven Eschenberg
Depends on your storage stack configuration, but the

yes to - Does one have to flag mounts with discard for both
crypttab and fstab in
order for TRIM to be in effect?
?
if the hole stack - then also lvm.conf?

thanks
L

Post by Sven Eschenberg
cryptsetup has discard disabled by default, for very good
reasons.
filesystems vary, so you'd have to check on your
particular filesystem documentation.
That's probably why you cannot find the ultimate answer -
there's none.
Regards
-Sven

Post by lejeczek
hi everyone
I realize question does not pertain LVM directly but
knowing that on the
list wonder around some very crypt-savvy guys&gals I
Does one have to flag mounts with discard for both
crypttab and fstab in
order for TRIM to be in effect?
Or just one? Just crypttab?
I've searched but failed to find an ultimate answer.
b.w.
L.
_______________________________________________
linux-lvm mailing list
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
linux-lvm mailing list
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

[Xen]

Post by lejeczek
Does one have to flag mounts with discard for both crypttab and fstab
in order for TRIM to be in effect?
Or just one? Just crypttab?

Cryptsetup has a flag but I don't know how it is evidenced in crypttab,
it is definitely required. The file system (ie. ext4, or tune2efs -o
discard) also requires it.