SolarisRunningFromCompactFlash

So you want to avoid wasting two disks for your boot partition on your OpenSolaris installation? Me too, I also want to be able to yank a card and drop in another if necessary for a quick recovery.

There's a couple other blog posts I've come across in trying to optimize performance, however I didn't see one that said the most obvious. If you want to boot from CF then install to CF, set your BIOS to boot from CF first, and off you go.

That said there's advantages to some of the methods, for example This URL will get your rpool compressed on a 4gb CF card (cache). There are other links I've seen talking about compressing your rpool - the one that sticks in my head is do NOT use gzip as that's not supported by the grub loader.

Personally I've done the simplest method, just install and boot. I didn't worry about compression, it wouldn't compress to a 2gb CF card (which we have several of for testing appliances), so I had to order a few cards anyway. After all, what's the cost difference between 2gb or 4gb? or 8gb... It's not that much, and you're likely going to need room to grow, snapshots, etc.

So once installed how do I optimize performance? It's horrible. The system is continually writing to the rpool for no apparent reason.

Well, I'm new to Solaris, new to dtrace, new to everything they've got for finding what is being done. I've got plenty of experience in other areas, so what i explored may not have been the most common things on Solaris (or may be, not sure) - I know from Linux and Windows (and others) experience you want to avoid writes, it's really that simple. So here's some things I've done:

zfs set atime=off rpool

Note: CONSIDER THE CONSEQUENCES of this - you're going to use ram instead of your disk for /var/tmp - However I see no "real" reason to have both a /tmp and a /var/tmp on a system - especially if we are building this for a specific appliance (i.e. for example a nas server):

ln -s /tmp /var/tmp

NOTE: You may want to copy all files first..
CAUTION: This thread talks a little about moving /var/tmp to /tmp


I don't have an explanation for why this makes the system work better, but with X running I had continuous problems / delays waiting on disk i/o to the CF card with no activity supposed to write to it. With X disabled all worked great.

#svcadm disable gdm

Other things to consider:

• Should you be building a custom live iso image instead? Would that work? I haven't tried this, however if the file changes persist across reboots if you use a CF / USB key instead of a CD then this seems MUCH faster (i.e. comparing the live usb keys that were given out at CommunityOne to testing on my own USB key). I haven't experimented with this any.
• What about mirroring? Two CF cards? Add a USB key also? Is it just like any other zpool for adding a mirror?
• Do you want to disable core dumps? ((SolarisManageCoreDumps|Managing Core Dump Settings)