On Wednesday, April 4, 2018 at 12:32:56 PM UTC-4, Chris Laprise wrote: > On 04/04/2018 11:50 AM, cooloutac wrote: > > On Sunday, April 1, 2018 at 5:45:54 PM UTC-4, Chris Laprise wrote: > >> On 04/01/2018 03:06 PM, 'awokd' via qubes-users wrote: > >>> On Sun, April 1, 2018 6:15 pm, cooloutac wrote: > >>>> Doesn't using trim on encrypted drive lessen security though? > >>> > >>> In my opinion, it's so marginal a security decrease it hardly bears > >>> mention. :) There's a link in the trim doc for further reading. > >>> > >> > >> I'd like to remind people: Discard and TRIM are not exactly the same thing. > >> > >> Commands like 'fstrim' only generate discards, and in a Qubes LVM setup > >> those discards will logically deallocate blocks in the pool, thus > >> freeing up space for filesystems. > >> > >> If you enable 'discard' or 'disktrim' or whatever they call it these > >> days in crypttab, that will result in discards being converted into > >> hardware TRIM commands. That is because the crypto layer is the one > >> closest to the hardware in our configuration. > >> > >> Does TRIM free up space? No. It helps the SSD maintain top write speeds > >> and perform more efficient wear-leveling. On some drives, it will also > >> cause the unallocated data to be wiped-out (according to vendor claims). > >> > >> Does fstrim free up space? Yes! Because it actually generates discards > >> and the name is misleading. > >> > >> IMO, the best thing to do is edit your dom0 /etc/fstab and add 'discard' > >> to the options for root fs '/'. That will free up space in a usable way > >> and you won't need to run fstrim. > >> > >> -- > >> > >> Chris Laprise, [email protected] > >> https://github.com/tasket > >> https://twitter.com/ttaskett > >> PGP: BEE2 20C5 356E 764A 73EB 4AB3 1DC4 D106 F07F 1886 > > > > according to these qubes doc it says it can hurt performance though if > > added to fstab? It says to use a systemd or cron job instead. Also says > > templates and vms already have trim enabled automatically. it also says if > > we are using luks to add it to crypttab or it won't work? > > That doc may need some clarifying. TRIM might hurt performance on older > SSDs as they wipe data blocks without caching the commands... but > without TRIM the discards are just changing block allocation tables. > Also, we're talking about dom0 where few filesystem operations are > performed; the domUs already all have discard enabled in fstab. > > > > > But is this really nescessary to do in dom0? Will it make any difference if > > all the templates and vms already have discard by default? And so does > > that mean we make the cron job for dom0 we also have to add discard to > > crypttab? > > The default rc5 dom0 config ran fstrim automatically once per week. IMO, > that's plenty of time for a user to do something which will lead to an > (unnecessary) out of space condition or at least be misinformed about > free space much of the time. > > The Qubes code has since been changed to add discard to dom0 fstab > during install, but I don't know if that made it to the 4.0 release iso. > I don't believe the crypttab setting has changed. > > TL;dr using discard is necessary when using thin pools (like its > necessary when using sparse disk image files) and relying on fstrim for > that means it should be run frequently. > > To me, the most interesting question all this raises is how close in > speed/performance are virtual disk operations on Thin LVM vs Btrfs since > they offer similar features and both incur block allocation processing > on two separate layers. > > > -- > > Chris Laprise, [email protected] > https://github.com/tasket > https://twitter.com/ttaskett > PGP: BEE2 20C5 356E 764A 73EB 4AB3 1DC4 D106 F07F 1886
I dunno man I keep hearing about how newer ssd's are supposed to be better. but I got a windows system with an m.2 and its horrible. can't use sleep when using on board audio card. still disabled indexing, superfetch, search and anything else that causes hdd space cause it would cause instability and corruption. Seems like right now every pc that has an old or new ssd using sleep mode, has instability after resume, no matter what os they are using. My Qubes dom0 got corrupted once, cause I was using an ssd when resuming from sleep, its even worse in 4.0. and that kind of sucks cause without magic packet waking it up i considered sleep a security feature. but I guess with ssd you can just shut it off and on even better and same thing basically. But are you saying in RC5 and on trim is enabled by default in dom0? -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/276086fd-8413-4710-ba4b-7439dfa12e7f%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
