Two particularly good quotes on the nature of faith, from the early to mid ’90’s sci-fi show Babylon 5:

Faith sustains us in the hour reason tells us we cannot continue, that our lives are without meaning

That’s all that faith requires; that we surrender ourselves to the possibility of hope

Have a wonderfully chilly day!

Categories: Life of Peawee, Quotables
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On our SAN at work, we use ZFS across it from a single head node to provide storage virtualization services, which are then exported via NFS to the rest of our machines on the network. At first, performance was a dog, especially on writing many small files to disk. This was indicative of having synchronous disk I/O, where all data is written straight to disk immediately before the writing program can go on, instead of having the data written to a cache in ram (aka asynchronous disk I/O). Synch’ed disk IO can slow down disk speeds a lot, as software accessing the filesystem has to wait for the disk writes to finish before it can go on, and there’s a lot more overhead involved with small files than with big files.

Upon some study, I went and turned off two ZFS module options in /etc/system that had more than a twofold increase in speed, especially when dealing lots of small writes.

set zfs:zil_disable=1
set zfs:zfs_noforcecache=1

These two settings made untarring the Linux source code (dozens of megabytes of small files) go from over 15 minutes for just linux/Documentation, to about 25 seconds. While on the SAN head node it’s under 15 seconds for the same operation, there’s still NFS overhead to worry about.

I also know that using these settings really annoy the ZFS developers, as they rightly should, as it mucks about with internals that effectively neuter ZFS’s very ingenious and effective data protection schemes. One of them, the noforcecache option, is mitigated by our disk controller hardware having battery backups for their on-hardware disk cache. The zil_disable is only backed by the SAN running off of UPS systems, however. Hopefully the ZFS devs can make the ZIL (the ZFS Intent Log) work correctly with NFS in the future without essentially forcing sync’ed IO.

Categories: Geeky Peawee
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So, Krystal and I are going to go for Halloween as Bond & Bond Girl. As such, I’ve decided I need to trim up a bit for the part, so today I started going to the gym to do that.

I discovered that my legs still are in incredible shape, and after 40 minutes on a leg-centric cardio machine, they still felt fresh as ever.

The rest of me, however, is a different story.

After climbing off the machine, I took a couple of cool-down walking laps around the track. I was able to keep up a nice walking pace. I simply wasn’t able to go any faster however, even if I wanted to. I just didn’t have any more left in me; if I had to do anything which required my body sending extra energy to my legs, I wouldn’t have been able to do it.

I do feel much better this afternoon though. I took a nap and methinks I’m going to sleep well through the night.

Now the bigger issue: for doing Bond, I’ve decided I’m going to darken my hair and shave the goatee. I don’t care about the hair, but I’ve had my goatee since my junior year of high school, so that’s going to simply be wierd to look in a mirror and not see goatee.

Categories: Life of Peawee
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