church of default » Note to Self

How to reclaim root reserved space on ext3

jim — Tue, 26 Jan 2010 22:44:55 +0000

First off look at what you’ve got now:

[root@sql2 ~]# df -P /
Filesystem         1024-blocks      Used Available Capacity Mounted on
/dev/mapper/VolGroup00-LogVol00  81269424  66551212  10534464      87% /

Then check how much is reserved blocks for root:

[root@sql2 ~]# tune2fs -l /dev/mapper/VolGroup00-LogVol00 | egrep 'Block count|Reserved block count'
Block count:              20971520
Reserved block count:     1045937

Thats 5%, which is a pretty common default. Like a lot of old defaults its based on old hardware, we can get away with a lot less and I could use the space elsewhere (SSD is expensive). So lets tune it down to 1%:

[root@sql2 ~]# tune2fs -m 1 /dev/mapper/VolGroup00-LogVol00
tune2fs 1.39 (29-May-2006)
Setting reserved blocks percentage to 1% (209715 blocks)

Verify that:

[root@sql2 ~]# tune2fs -l /dev/mapper/VolGroup00-LogVol00 | egrep 'Block count|Reserved block count'
Block count:              20971520
Reserved block count:     209715

Looks good, lets see how much space we got:

[root@sql2 ~]# df -P /
Filesystem         1024-blocks      Used Available Capacity Mounted on
/dev/mapper/VolGroup00-LogVol00  81269424  66551756  13878808      83% /

Sweet, touch over 3GB

what exactly do the numbers in iostat mean?

jim — Sun, 10 Jan 2010 03:53:17 +0000

You need better storage.

But if you really want to know the details, the Baron will tell you:

How Linux iostat computes its results at Xaprb.

How to figure out the WWN of FC HBA cards in CentOS/RHEL

jim — Sun, 15 Nov 2009 17:12:03 +0000

Methods to retrieve WWPN and WWNN from FC HBA cards

Haven’t tried these yet but wanted to stick this link somewhere. Man I wish FC would just go away already.

Is the internet broken?

jim — Wed, 04 Nov 2009 22:04:34 +0000

Sometimes you do a pretty good job of ruling out your shit and are convinced that somewhere out there the internet is broken a little bit… but how do you know?

*shrug* but here’s some links:

NANOG

Keynote’s Internet Health Report

Outages.org

renesys blog (good for in depth day-after info)

nagios-config.png

jim — Fri, 23 Oct 2009 14:58:53 +0000

see, its easy

source

using sed to replace a single value in a config file

jim — Mon, 19 Oct 2009 19:27:56 +0000

Which happens to be the only thing I can do with sed
/bin/sed -i'' -e's/foo/bar/' /etc/filename

RAID Array estimated IOPS calculator

jim — Sat, 17 Oct 2009 18:23:55 +0000

Check this thing out:

wmarow’s disk & disk array calculator

Man I wish I had something like that 4 years ago.

howto change the user of an svn checkout

jim — Tue, 25 Aug 2009 15:52:56 +0000

[Snaplogic-dev] Switching SVN checkout users .

I didn’t actually use it, I wound up blowing away the checkout and redoing it as the proper user, but this looked like a handy link to keep around. And thats really what this blog is, me talking to myself. Also russian comment spammers, hi guys!

CentOS: How to scan the SCSI bus with a 2.6 kernel

jim — Wed, 08 Jul 2009 20:19:51 +0000

CentOS: How to scan the SCSI bus with a 2.6 kernel.

Looks like Tim stopped updating awhile ago, but this is a handy post I wanted to have a link to here.

A handy uptime and downtime conversion cheat sheet | Royal Pingdom

jim — Sat, 18 Apr 2009 03:49:38 +0000

A handy uptime and downtime conversion cheat sheet | Royal Pingdom.

Doesn’t show my personal favorite though, 99.95, or 20-minutes/month. Its nice to work in the media industry.