On 21/07/13 22:31, luis jure wrote: > > OK, now i have my system successfully installed and running on my new SSD. > now i have to decide what to do with the rest of the disk (it's a 256MB > samsung). > > the first big question is: what about swap? i found some web pages > (perhaps old) stating that it's not wise to put swap on the SSD because of > all the read/writes. but apparently from what i read on the recent > thread on this list, that shouldn't be much of a concern now. > > i also read somewhere that if you have swap on the SSD and want to avoid > unnecessary read/writes, you can reduce swappiness. i have 12GB RAM and i > think normally i don't really need swap space on disk, so i thought that > could be a good idea. > > so what i'm planning to do now is: > > - put swap on the SSD > - reduce swappiness > - put /var/tmp/portage on tmpfs > > so, do you guys think that's a good setup? >
swap: this will make one of the bigger speedups to the system when you need swap. swap is good - yes you can do without it, but the day comes when you REALLY do want it, and ... [crash!] ... otherwise it can just sit there waiting :) /etc/sysctl.conf: #vm.swappiness=1 #vm.vfs_cache_pressure=50 these were recommended to me for running vm's and seem to do the job (usually I am running with a several GB of swap (16G ram, 16G swap) in use ... these settings definitely minimise it though big rsync jobs stall when it fills ram+swap. /var/tmp/portage is a more difficult one ... a long thread way back (Dale, I think you were in it) looking at speed showed there was no speed advantage to compiling in tempfs because spinner) disk caching was so good the data only hit the disk when necessary. I presume the same will apply with compiling and SSD's in that the actual writes will be minimal (in the scheme of things) so it shouldn't be a worry. My experience with compiling in tempfs is that it works, but has a much higher failure rate than on disk - i.e., things like OO/Lo, KDE, gcc and glibc have large space requirements that you must make sure tmpfs can satisfy before you start. And if its a busy machine actively using lots of ram it gets "hard". I am making the point that most machines today are way overprovisioned but when you are near the edge, saying things like I gave xGB ram and never needed swap, so you wont either is misrepresenting the situation. BillK
