* [dm-crypt] Problem_wiping @ 2019-04-19 13:13 Dernsen 2019-04-20 8:00 ` Arno Wagner 2019-04-20 14:18 ` Robert Nichols 0 siblings, 2 replies; 4+ messages in thread From: Dernsen @ 2019-04-19 13:13 UTC (permalink / raw) To: dm-crypt [-- Attachment #1: Type: text/html, Size: 2083 bytes --] ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [dm-crypt] Problem_wiping 2019-04-19 13:13 [dm-crypt] Problem_wiping Dernsen @ 2019-04-20 8:00 ` Arno Wagner 2019-04-20 14:18 ` Robert Nichols 1 sibling, 0 replies; 4+ messages in thread From: Arno Wagner @ 2019-04-20 8:00 UTC (permalink / raw) To: dm-crypt Hi, what kind of problem do you think there is? I do not see any. You just seem to have a slow dsk... Regards, Arno On Fri, Apr 19, 2019 at 15:13:27 CEST, Dernsen wrote: > Hi, > I prepared a partition on my hdd (no ssd) as described in cryptsetup > FAQ (intel i3 3rd gen. ; 4gb ram): > Test 1. dd urandom direct on partition: > root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/urandom > of=/dev/sda3 > 55566139392 Bytes (56 GB, 52 GiB) kopiert, 1611 s, 34,5 MB/s > dd: Fehler beim Schreiben von '/dev/sda3': Auf dem Gerät ist kein > Speicherplatz mehr verfügbar > 3313+0 Datensätze ein > 3312+0 Datensätze aus > 55574528000 Bytes (56 GB, 52 GiB) kopiert, 1630,73 s, 34,1 MB/s > root@pocket-pc:/home/dernsen# > Test 2. dm-crypt + dd on device-mapper: > root@pocket-pc:/home/dernsen# cryptsetup open --type plain -d > /dev/urandom /dev/sda3 to_be_wiped > root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/zero > of=/dev/mapper/to_be_wiped > 55566139392 Bytes (56 GB, 52 GiB) kopiert, 1536 s, 36,2 MB/s > dd: Fehler beim Schreiben von '/dev/mapper/to_be_wiped': Auf dem Gerät > ist kein Speicherplatz mehr verfügbar > 3313+0 Datensätze ein > 3312+0 Datensätze aus > 55574528000 Bytes (56 GB, 52 GiB) kopiert, 1554,81 s, 35,7 MB/s > root@pocket-pc:/home/dernsen# > There is almost no difference in speed. > 1. Did i do any mistake? > 2. Is this recommodation still up to date? > Best > Sebastian > _______________________________________________ > dm-crypt mailing list > dm-crypt@saout.de > https://www.saout.de/mailman/listinfo/dm-crypt -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@wagner.name GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [dm-crypt] Problem_wiping 2019-04-19 13:13 [dm-crypt] Problem_wiping Dernsen 2019-04-20 8:00 ` Arno Wagner @ 2019-04-20 14:18 ` Robert Nichols 2019-04-20 17:09 ` Arno Wagner 1 sibling, 1 reply; 4+ messages in thread From: Robert Nichols @ 2019-04-20 14:18 UTC (permalink / raw) To: dm-crypt On 4/19/19 8:13 AM, Dernsen wrote: > Hi, > > I prepared a partition on my hdd (no ssd) as described in cryptsetup FAQ (intel i3 3rd gen. ; 4gb ram): > > Test 1. dd urandom direct on partition: > > > root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/urandom of=/dev/sda3 > 55566139392 Bytes (56 GB, 52 GiB) kopiert, 1611 s, 34,5 MB/s > dd: Fehler beim Schreiben von '/dev/sda3': Auf dem Gerät ist kein Speicherplatz mehr verfügbar > 3313+0 Datensätze ein > 3312+0 Datensätze aus > 55574528000 Bytes (56 GB, 52 GiB) kopiert, 1630,73 s, 34,1 MB/s > root@pocket-pc:/home/dernsen# > > > > Test 2. dm-crypt + dd on device-mapper: > > root@pocket-pc:/home/dernsen# cryptsetup open --type plain -d /dev/urandom /dev/sda3 to_be_wiped > root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/zero of=/dev/mapper/to_be_wiped > 55566139392 Bytes (56 GB, 52 GiB) kopiert, 1536 s, 36,2 MB/s > dd: Fehler beim Schreiben von '/dev/mapper/to_be_wiped': Auf dem Gerät ist kein Speicherplatz mehr verfügbar > 3313+0 Datensätze ein > 3312+0 Datensätze aus > 55574528000 Bytes (56 GB, 52 GiB) kopiert, 1554,81 s, 35,7 MB/s > root@pocket-pc:/home/dernsen# > > > > There is almost no difference in speed. > > 1. Did i do any mistake? > 2. Is this recommodation still up to date? Recent kernels (3.x and newer) have a much faster /dev/urandom, so there is no longer a speedup when overwriting with encrypted zeros. With a 2.6 kernel, I measure just 13 MB/s from /dev/urandom, whereas a 3.10 kernel on the same hardware achieves 251 MB/s from /dev/urandom. Perhaps it's time to update the FAQ. -- Bob Nichols "NOSPAM" is really part of my email address. Do NOT delete it. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [dm-crypt] Problem_wiping 2019-04-20 14:18 ` Robert Nichols @ 2019-04-20 17:09 ` Arno Wagner 0 siblings, 0 replies; 4+ messages in thread From: Arno Wagner @ 2019-04-20 17:09 UTC (permalink / raw) To: dm-crypt Interesting, I had not noticed. You are right though, I get 260MB/s with 5.0.x on hardware that used to be about 10x slower for this. This is even a bit faster than the ciphers cryptsetup offers. Indeed time for an update. Should be able to get to it some time after Easter. Thanks! Arno On Sat, Apr 20, 2019 at 16:18:50 CEST, Robert Nichols wrote: > On 4/19/19 8:13 AM, Dernsen wrote: > >Hi, > > > >I prepared a partition on my hdd (no ssd) as described in cryptsetup FAQ (intel i3 3rd gen. ; 4gb ram): > > > >Test 1. dd urandom direct on partition: > > > > > >root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/urandom of=/dev/sda3 > >55566139392 Bytes (56 GB, 52 GiB) kopiert, 1611 s, 34,5 MB/s > >dd: Fehler beim Schreiben von '/dev/sda3': Auf dem Gerät ist kein Speicherplatz mehr verfügbar > >3313+0 Datensätze ein > >3312+0 Datensätze aus > >55574528000 Bytes (56 GB, 52 GiB) kopiert, 1630,73 s, 34,1 MB/s > >root@pocket-pc:/home/dernsen# > > > > > > > >Test 2. dm-crypt + dd on device-mapper: > > > >root@pocket-pc:/home/dernsen# cryptsetup open --type plain -d /dev/urandom /dev/sda3 to_be_wiped > >root@pocket-pc:/home/dernsen# dd bs=16M status=progress if=/dev/zero of=/dev/mapper/to_be_wiped > >55566139392 Bytes (56 GB, 52 GiB) kopiert, 1536 s, 36,2 MB/s > >dd: Fehler beim Schreiben von '/dev/mapper/to_be_wiped': Auf dem Gerät ist kein Speicherplatz mehr verfügbar > >3313+0 Datensätze ein > >3312+0 Datensätze aus > >55574528000 Bytes (56 GB, 52 GiB) kopiert, 1554,81 s, 35,7 MB/s > >root@pocket-pc:/home/dernsen# > > > > > > > >There is almost no difference in speed. > > > >1. Did i do any mistake? > >2. Is this recommodation still up to date? > > Recent kernels (3.x and newer) have a much faster /dev/urandom, so there is no longer a speedup when overwriting with encrypted zeros. With a 2.6 kernel, I measure just 13 MB/s from /dev/urandom, whereas a 3.10 kernel on the same hardware achieves 251 MB/s from /dev/urandom. > > Perhaps it's time to update the FAQ. > > -- > Bob Nichols "NOSPAM" is really part of my email address. > Do NOT delete it. > > _______________________________________________ > dm-crypt mailing list > dm-crypt@saout.de > https://www.saout.de/mailman/listinfo/dm-crypt -- Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@wagner.name GnuPG: ID: CB5D9718 FP: 12D6 C03B 1B30 33BB 13CF B774 E35C 5FA1 CB5D 9718 ---- A good decision is based on knowledge and not on numbers. -- Plato If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-04-20 17:09 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-04-19 13:13 [dm-crypt] Problem_wiping Dernsen 2019-04-20 8:00 ` Arno Wagner 2019-04-20 14:18 ` Robert Nichols 2019-04-20 17:09 ` Arno Wagner
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