Hi Lasse, have you done any benchmarks for kcryptd to determine the bottleneck is your CPU? My intuition would be that for this setup and the stated speed it is likely, but better be sure than to optimize nthe wrong parameter. As to options, basically a faster CPU and/or more cores is one, the other is SSD, if the bottleneck is with the disks. A third one is a different controller and/or bus attachment of the controller. It is also possible that a singel disk slows things down. HDDs can get donw to 50% of the start-of-disk speed somehwere between the 50% coapacity mark and the end. The second thing you need to ask you, is if you are only interessded in linear read speed. If not, an increase 70 -> 100 may well be insigificant in the access mix you are using and not worth the investment. Gr"usse, Arno On Thu, Nov 11, 2010 at 11:49:16AM +0100, Lasse Jensen wrote: > Hi. I have a RAID 5 array with 3 (soon upgrading to 4 + hotspare = 5) > encrypted drives connected to a system with a Core 2 Duo @ 2.5 ghz running > Debian Squeeze. > Each drive has been formatted with > > cryptsetup luksFormat /path/to/device > > And put together in a array with > > mdamd -C /dev/md0 --raid-level=5 /path/to/first-device /path/to/third-device > /path/to/third-device > > It works great, and encrypting the devices separately allows me to run more > than one instance of kcryptd, thus using both cores in my server. It > compensates for the overhead of encrypting the checksumming data seperately, > compared to raw devices -> RAID -> encryption and still give me improved > speed. > > At the moment, i get 70 mb/s sequential read speed locally. I would like to > boost it to at least 100 or even more, as 1) the raw drives support way more > and 2) i would like to fill my gigabit ethernet when copying files over the > network. > > Now, what are my options? > > A quadcore CPU like the Q6600 would double the number of cores and > theoretically double the throughput, but at cost of idle power. Note that > the server is idle most of the time. > A core i5. They have AES support in hardware, but it's an expensive solution > and i'm not even sure it has Linux support. > A PCI or PCIe based card, like the HiFN cards, but what card should i look > for and what speed should i expect? > Using the CUDA cores of my nVidia card, but no driver seems to exists for > that. > > The first option is pretty straight forward, but what about the rest? Or are > there any other options i havent thought of? > > -- > Lasse Jensen (fafler at gmail dot com) > _______________________________________________ > dm-crypt mailing list > dm-crypt@xxxxxxxx > http://www.saout.de/mailman/listinfo/dm-crypt -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@xxxxxxxxxxx GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
