I got a new Samsumg 830 512GB SSD which is supposed to be very high performance. The raw device seems fast enough on a quick hdparm test: /dev/sda4: Timing cached reads: 14258 MB in 2.00 seconds = 7136.70 MB/sec Timing buffered disk reads: 1392 MB in 3.00 seconds = 463.45 MB/sec <<<< which is 4x faster than my non encrypted spinning disk, as expected. But once I encrypt it, it drops to 5 times slower than my 1TB spinning disk in the same laptop: gandalfthegreat:~# hdparm -tT /dev/mapper/ssdcrypt /dev/mapper/ssdcrypt: Timing cached reads: 15412 MB in 2.00 seconds = 7715.37 MB/sec Timing buffered disk reads: 70 MB in 3.06 seconds = 22.91 MB/sec <<<< gandalfthegreat:~# hdparm -tT /dev/mapper/cryptroot (spinning disk) /dev/mapper/cryptroot: Timing cached reads: 16222 MB in 2.00 seconds = 8121.03 MB/sec Timing buffered disk reads: 308 MB in 3.01 seconds = 102.24 MB/sec <<<< I used aes-xts-plain as recommended on http://www.mayrhofer.eu.org/ssd-linux-benchmark gandalfthegreat:~# cryptsetup status /dev/mapper/ssdcrypt /dev/mapper/ssdcrypt is active. type: LUKS1 cipher: aes-xts-plain keysize: 256 bits device: /dev/sda4 offset: 4096 sectors size: 926308752 sectors mode: read/write I tried cryptsetup luksFormat --align-payload=8192 the first time, so my offset was 8K, but that did not make a difference in speed. gandalfthegreat:~# lsmod |grep -e aes aesni_intel 50443 66 cryptd 14517 18 ghash_clmulni_intel,aesni_intel aes_x86_64 16796 1 aesni_intel Kernel: 3.4.4-amd64 gandalfthegreat:~# cryptsetup --version cryptsetup 1.4.3 I know that SSDs are weird and all, but getting a raw device speed of a mere 23MB/sec down from 463MB/s and compared to 102MB/s for a similarly spinning drive, is a problem, is it not? Any suggestions would be appreciated. Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
