PAM Trick: So today at work we did a massive head upgrade (from 6070′s to 6080′s) as well as some shelf swaps. The new heads have Flash Cache cards in them, half a terabyte of memory on a card used for caching, which ideally should speed up stuff, and keep the overal IOPs own on the busiest shelves. Now I will give credit where credit is due, my coworker Dalvenjah (yes that is a handle), did a very slick thing to get a mysql db into cache quickly. The database was stopped, he cd’d into the data dir, then ran cat * > /dev/null which sequentially read the files, essentially pumping them into the cache, as the first read comes from disk, all subsequent reads came from cache, the speedup was awesome. Just thought I would share :), I am quite sure you can think of other just as slick ways to get data into cache.

Here’s a quick little tip:

Sometimes when working with filers (on the cli) you need to get a directory listing for a volume. Unfortunately there is no ‘ls’ *command, so you can do this:

sudo ssh filername "priv set advanced; ls /volume_name"

so a real world example would be:

sudo ssh filername "priv set advanced; ls /vol/vol0/etc"

Hope this helps.

*I know you can ssh or rsh to the filer and run priv set advanced, and then run the ls command but that is functionally the same as running as root, and should be avoided unless absolutely necessary.