Verify backups before implementing changes

Going to make a change to a machine?

Verify that you have good colds before you go through.

Almost every change or upgrade plan I have starts off with:

1. Day after colds: Verify backups for hosts {a,b,c,d,e,f,g,h} 
2. Day of implementation:  Verify backups for hosts {a,b,c,d,e,f,g,h}

If that backup isn't good, either take a good backup immediately before preceding or reschedule your implementation for a window after the next full backup.

I've had this save me a time or two. A previously bulletproof backup decided to cook off the week of one of my upgrades.

Oracle 10g on ZFS IOPS

I was reviewing a machine of ours that people had been complaining about. The disks were horribly busy and it made it difficult to tell what was hurting the performance in Oracle Apps. zpool iostat for the DB pool was constantly running about 4,000-6,000 read OPs at up to 65MB/sec, which seemed off. The ARC prefetch misses were really high and it occurred to me that ARC was prefetching at all. After disabling file-level prefetch the zpool iostat numbers dropped to 0-150 read OPs immediately. I really thought I had broken it, but I logged in to the apps and tested things out, everything was snappy.

Many thanks to ZFS Evil Tuning guide.

So you have a bunch of IE Favorites and want to take them to Firefox

BUT you forgot to export them to HTML before you nuked Windows.
You need a way to parse the URL file and strip out the URL= field, adding it to an a href and using the filename as the bookmark name. I use tofrodos to fix the ^Ms in the files, they really mess with awk's output.

cd /mnt/sdb1/Doc*/Jodie/Favorites
fromdos *.url
awk -F"URL=" '/^URL=/ { sub(/.url$/,NULL,FILENAME); print "<a href=\""$2"\">"FILENAME"</a><br>" }' *.url > out.html


Now import `out.html` into Firefox. Ta-da!
(Blogger tried really hard to eat that HTML. First example had sed stripping the .url from FILENAME, but I realized I could have awk do that.)


-Jodie