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MirBSD switching to pkgsrc, 2011-01-23 14:25:00 #
MirBSD/MirOS, a fork of OpenBSD, is adopting pkgsrc as its pkg management tool.

This is close on the heels of DragonflyBSD doing the same thing. I can't say I blame them as packaging software is a painful experience with, as far as I can tell, limited reward. :)

Welcome!

tags: pkgsrc



Linux ext4 journaling and workloads, 2011-01-20 12:08:19 #

Today at work I found out some details about ext4 and how its journal settings can really affect different workloads.

The default data=ordered and data=writeback give good performance for operations on larger files.
dd if=/dev/zero bs=1024 count=1000000 of=/var/dout2 and variants were 2-3x faster than ext3
perl -e '$|++; for($x = 0; $x < 10000; $x++) { open(FH, "+>", "/var/file") or die "$!"; print FH "hello, world\n"; close FH; }' was 50x SLOWER, however.
Another interesting point on this is to run tail -F /var/file during the test on ext4 vs ext3. It will become pretty obvious where the problem is- ext3 only writes the contents of the file once whereas ext4 does what you thought you asked it to do.

Switching to data=journal basically turned ext4 into ext3 in terms of performance, making my 1GB dd's slower and my perl script faster

tags: linux



NetBSD core dump tips, 2011-01-19 10:47:35 #
Today I was investigating a varnish crash on my system and wondering why my messages looked like this:
pid 27586 (varnishd), uid 32767: exited on signal 11 (core not dumped, err = 1)

After some time I figured out that it wasn't a varnish setting or anything like that, it was more likely a problem with netbsd not allowing the core file to be written!

sysctl(8) has an example.
sysctl(7) has a definition.
default sysctl.conf has another tip.

Anyway, change the following in /etc/sysctl.conf:

kern.defcorename=/var/tmp/%n.core

And run:
sysctl -w kern.defcorename=/var/tmp/%n.core

Now core files should end up in /var/tmp, which has sticky bit and should allow for anyone to write.

tags: netbsd



NetBSD gets Wasabi Systems iSCSI, 2011-01-10 13:35:24 #
libisns contribution from Wasabi Systems, Inc

and old mention of wasabi which may no longer be true..

Even though netbsd has had iSCSI for a while, this might improve performance and has been out in the real market on enterprise installations for years, so it's definitely proven.

tags: netbsd



perl re alternative syntax, 2011-01-07 10:14:33 #
maatkit schooling me on perl

You'd think after ten years of using perl I would remember some of its features, but of course that doesn't stop me from opening useless feature requests. :)

Using this style:
"(?imsx-imsx:pattern)"
You can just use m// and skip having modifiers at the end.

Example:

$ echo "hellO"|perl -ne 'print if m/lo/i;'
hellO
$ echo "hellO"|perl -ne 'print if m/lo/;'

$ echo "hellO"|perl -ne 'print if m/(?i:lo)/;'
hellO

Thus, when you want to have mk-kill only function on SELECT statements, you can use --match-info '(?i-xsm:select)'

tags: perl



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