On Tue, 2011-02-22 at 18:47 -0500, Greg Freemyer wrote:
On Tue, Feb 22, 2011 at 5:20 PM, Fr David Ousley
wrote: Friends --
I'm installing Opensuse 11.3 on a new machine. It has an SSD drive, and two RAID 1 (mirrored) hard drives. I was planning to put the /boot and /swap on the SSD for speed (unless you experts -- which I am not -- tell me that that's not a good idea),
I would not put the SSD on swap for "speed".
If you are using swap enough that speed matters, you will wear out your SSD long before you would otherwise.
ie. Low-end SSD is designed for about 5,000 write cycles per Erase Block (EB). High-end for about 100,000 I think. Wear leveling allows you to spread that load around to unused EBs, but it will still be a problem.
If you are hitting swap so much you care about speed, then SSD is a poor solution.
If you're hitting it hard, either leave it on rotating disk or get more ram.
If you only use swap now and then, but get frustrated that your whole machine slows down, then maybe. The trouble is you could start using swap more and more frequently and not realize it. Thus you wear out that expensive SSD for little real value.
Absolutely true, In the bad-old-days, swap was a mere fact-of-life. But with the price of mem dropping continously things have changed. In general, swap should be treated as the safety lane on the high way: "It is there, but should never use it unless emergencies arises" Otherwise, there is something wrong in the system.... So if you _add_ a SSD only for speeding up things, very well, put all the things there that hardly changes: /boot, /usr, /lib, perhaps mount them read-only. And keep stuff that changes continuously (/var, /srv, /tmp) on traditional disks. Other story is however if you _only_ have sdd, for instance for noise, power consumption. Some partitions (/tmp, /var/run) can entirely be placed in mem, using tmpfs, thus increasing the claim on mem. Leaves us with swap in that condition: If you don't define swap (possible) and a process gets greedy, the much feered Out-Of-Mem steps in and might kill processes you rather would like the live. On the other hand, as clearly stated above, swap on SDD will have a bad impact on the life expectency of your SDD. hw -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org