Le vendredi 29 juillet 2011 11:32:02 John Robinson, vous avez écrit : > On 29/07/2011 00:53, Xavier Brochard wrote: > > Le jeudi 28 juillet 2011 20:31:10 Doug Ledford, vous avez écrit : > >> On 07/20/2011 08:59 AM, brian.foster@xxxxxxx wrote: > [...] > > >>>> On 07/19/2011 11:32 AM, Roman Mamedov wrote: > [...] > > >>>>> See http://bcache.evilpiepirate.org/ > > [...] > > >>> https://github.com/facebook/flashcache > >> > >> Having not looked at those two, I can say that an md raid1 with two hard > >> drives and one SSD works *very* well. It's blazing fast. Here's how I > >> set mine up: > >> > >> SSD: three partitions, one for boot, one for /, and one for ~/repos > >> (which is where all my git/cvs/etc. checkouts reside) > >> hard disks: four partitions, one for boot, one for /, one for /home, one > >> for ~/repos > >> > >> Then I created four raid1 arrays like so: > >> > >> mdadm -C /dev/md/boot -l1 -n3 -e1.0 --bitmap=internal --name=boot > >> /dev/sda1 --write-mostly --write-behind=128 /dev/sdb1 /dev/sdc1 > >> mdadm -C /dev/md/root -l1 -n3 -e1.2 --bitmap=internal --name=root > >> /dev/sda2 --write-mostly --write-behind=1024 /dev/sdb2 /dev/sdc2 > >> mdadm -C /dev/md/home -l1 -n2 -e1.2 --bitmap=internal --name=home > >> /dev/sdb3 /dev/sdc3 > >> mdadm -C /dev/md/repos -l1 -n3 -e1.2 --bitmap=internal --name=repos > >> /dev/sda4 --write-mostly --write-behind=1024 /dev/sdb4 /dev/sdc4 > >> > >> Works for me with stellar performance. Treats the SSD as the only > >> device that matters on the three arrays it participates in with the hard > >> drives there merely as a backing store for safety in case the SSD blows > >> chunks some day. Obviously, if you need some other aspect of your home > >> directory to have the SSD benefit then modify to your tastes, but all my > >> scratch builds happen under ~/repos and the thing flies when compiling > >> stuff compared to how it used to be. > > > > One thing you didn't said is the respective size of the SSD and HD > > partitions. How did you determine them? > > Since he's running RAID-1, the partitions on the SSD and HDDs must be > the same size. Note that the rest of the space on the HDDs was given to > /home and was not mirrored on the SSD. Oh... I thought It was more like Mike's request: "a RAID 1 array using two equal size HDD and one smaller and faster SSD" Xavier xavier@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
