d.piddy's piece

Hardware vs. Software RAID

2008-04-22T22:25:00Z

This article came up in my Planet SysAdmin feed talking about Linux software RAID and LVM. I’ve been using software RAID more recently and it’s fine for simple cases but there are many situations where having a hardware RAID card just makes things easier.

For example, I have a machine with 7 500G drives. Ideally, I want a 24G root filesystem, 4G swap and the rest for LVM, all striped using RAID 5 to maximize the space for LVM. It’s simple with a hardware RAID card: just put the 7 drives in an array and divvy up the single large device you get in Linux. One partition for the root, another for swap and a third for LVM.

With software RAID, this doesn’t seem to exactly possible. The big problem is that grub can’t boot from RAID 5 devices. To work around that, I ended up having to create partitions for the root, swap and LVM on the first two drives and create single large LVM partitions on the rest. I created two RAID 1 devices (which grub can boot) using the root and swap partitions on the first two drives and a RAID 5 for LVM using the third partitions on the first two drives and the only partitions on the remaining drives. But I lost 113G in LVM space since the partitions used to make up the LVM RAID 5 were smaller on the first two drives.

I guess I could create a RAID 1 of the smaller LVM partitions on the first two drives, a RAID 5 of the all-disk partitions on the rest of the drives and use both as PVs in my VG. Seems pretty complex, though, and I’d still lose some space.

On the other hand, software RAID definitely has advantages in that it works the same way on any machine. I get really annoyed with some hardware RAID cards and their silly limits: no more than X drives in an array, no arrays larger than Y, etc.). Software RAID in Linux also provides consistent notification methods.

Three Excellent Softwares

2007-05-15T04:43:00Z

You should know about these.

Dovecot—the best IMAP server ever. If you use Cyrus and want to convert, I highly recommend cyrus2courier which can convert Cyrus mailboxes to Courier or Dovecot-compatible Maildirs. I have my own hacked up version here that knows how to read the particular version of Cyrus mailboxes I was converting.

Munin—simple “historical data” monitoring. court3nay turned me on to this; not sure how I lived without it so long. It sure beats running iostat manually when you think something is up. Plugins are really easy to write for it, too.

Perdition—extremely lightweight IMAP/POP3 proxy. I recently converted a bunch of Cyrus mailboxes to Dovecot and this was the perfect program to be my man in the middle as I moved people over. The machine that’s running it peaks at about 1700 processes (3200 total connections, 10+ megabits) and doesn’t break a sweat.

Cool, huh? Munin and Perdition are easily installed from the Ubuntu universe repository. Dovecot just hit 1.0 so you might want to compile it for now…there might be packages for it somewhere.

Puppet and Related Thoughts

2007-03-10T05:14:00Z

I’ve been looking into Puppet a lot lately for centralized management and I think it’s pretty cool. It’s written in Ruby and the author and community are both very welcoming and helpful.

Along the lines of Puppet, I’ve had a system administration reawakening of sorts lately and I’ve been researching ways to make systems I create and maintain better. It seems so easy on the surface; make systems that do the same things the same and provide well-documented and hopefully automated processes to bring new ones to life. The Puppet author puts it in terms of car manufacturing: cars used to be built by hand but they aren’t anymore for obvious reasons. Why should systems and services be any different? We have the technology!

Here are the main references I’ve been referring to for this kind of info lately:

The puppet trac and its related documentation. Also this presentation was very good.
Infrastructures.Org, which I found as the result of an unrelated Google search is what started all this for me. isconf is also interesting.
The Practice of System and Network Administration, a generally OS-independent book about administration theory and best practices

Need an HDMI Cable?

2007-03-02T16:14:00Z

Be sure to check your local BigLots. I just got a Vizio 42 inch LCD (which is awesome) and someone suggested I check there for a cable. I found them for $12.

Folding Laundry is Getting Things Done

2007-02-01T04:42:00Z

I’ve been wanting to write something about Getting Things Done for a long time but hadn’t figured out a way to sum it up. This might be a start.

I’ve never been much of a laundry folder. I hang shirts up so they don’t get wrinkled but as far as socks and things like that they usually get stuffed in a drawer or left in a pile on top of something. As I need things, like a pair of socks, I rummage through the pile trying to find a sock. Then I do it some more to find one that matches it. Not a big deal but it does take some time and it can be rather frustrating.

If I pair and store my socks somewhere sensible when they come out of the wash, I do the rummaging process once. It might take longer than it would to find one pair of socks in a pile but in the long run I’m saving a lot of time and possible frustration. And in the morning when I need a pair of socks, there’s no thinking involved. Just grab a pair and go!

That’s one way to sum up GTD. Do the thinking ahead of time so when the time comes to do something there’s no rummaging required—just pick an action and do it!

PDF::Writer appeases the tax man

2007-01-27T03:54:25Z

I’ve used PDF::Writer for a few things in the past but nothing major. This past week a customer was having trouble with their payroll software and couldn’t print W2’s. See where this is going?

The core of the problem was not being able to apply a database update that would let their software do the printing. That’s a whole separate story in itself, but it was a real pain. The vendor eventually gave up and said any more troubleshooting would have to be billed. Since the customer is soon moving to new software that will replace this current suite, they didn’t want to spend any unnecessary money on it and I didn’t want them to either.

The only reason they needed this particular update was to print W2’s. I made the mistake initially of assuming that this update was tied to the gathering of the data in addition to the printing of it. But that was not the case. In passing I discovered they had been pulling the data out for use in Excel for over a week at that point. Knowing that, I thought I could work some magic by printing them myself. It sounded a little drastic but time was running out and the vendor was getting nowhere. The customer was going into “we’ll just have to type them up ourselves” mode, too.

I sat down with one of their pre-printed W2 forms and a ruler and had something respectable in no time. It took some more work to get everything just right…I’d say within an hour and a half, after printing 10 test sheets, it was perfect. So easy. The customer was thrilled they wouldn’t have to work over the weekend. I was thrilled that they wouldn’t be doing unnecessary manual typing. The vendor was still scratching their heads.

Christmas in Canada

2006-12-21T05:04:29Z

Viki and I will be on our way to Kingston, Ontario tomorrow for Christmas and New Year’s. We are both very excited! I’ve only been to Kingston once but that was in the summer of 2005. It was very nice and I’m looking forward to seeing how it is in the winter time…I hope I can stay warm enough.

Her dad and I will be messing around with Asterisk while I’m up there which should be fun. He’s been using it at home for a while and I’m getting ready to do my company’s first install the weekend after we get back. We’re using Polycom 601’s which can be seen here. They have been great so far but I’m hoping to get some more time for experimenting while I’m up there. Thanks to the magic of Parallels I can have a server set up wherever my laptop is.

Anyway, I’m taking my trusty Canon PowerShot A80 (still kickin’) and should be putting pictures up on Flickr. Merry Christmas to everyone and happy New Year!

Wii Fun

2006-11-25T17:15:42Z

The Wii rocks. Plain and simple. Yeah, it doesn’t have the best graphics but it makes up for it by being oh so fun. I have been meaning to write about mine since I got it but wanted to wait until I took it to my sister’s house to see how it did. Here’s the brief story of how I got it and how it held up.

The way I ended up getting it was pretty fun, too. On Saturday night (the release being at 12:01am that night), after attending the night portion of the Balloon Festival, I wanted to check out the crowd at the Wal-Mart that’s right by us. The employees said a line would start forming outside Layaway at 10pm but this was around 7:30pm and I was wondering who would be there already. It was pretty full. The Wal-Mart people had set up benches for people to sit on as they lined up which I thought was nice but my chances weren’t looking too good. We left there and I called the other Wal-Mart in town and the guy thought he saw 13 people lined up but he wasn’t sure how many Wiis they were getting. Viki took me down there and I discovered they had 28 numbered chairs set up; one for each Wii they had. And what luck! They had 2 chairs left. I took my spot and Viki was nice enough to get me something to eat and bring my iPod and DS Lite. :) She’s the best! So I waited until 12 and they called us my number and let us make our purchase. I just got the base system for now…I’ll buy a game or two after the holidays. I did pick up an extra remote at Target a couple days later, though.

Viki and I have had so much fun playing it…and we still just have Wii Sports! I’m teetering around the Pro level in baseball and Viki enjoys playing pretty much all the different sports. Last night, we took it to my sister’s and it was a great hit with everyone as you can see here. The older boys seemed to know right away basically how it worked but they had a hard time doing “real fake” motions like swinging at a pitch without actually having a bat or bowling without actually holding a ball. It took Jenn and Tom some getting used to but once they got the hang of it they loved it. We played all the different sports but I think tennis and bowling were the overall favorites. Tom especially liked how spin could be put on the ball in bowling…he really got into it. :P

I kept joking about this review which declares Wii Sports quite possibly the greatest videogame in the history of the universe but I have to say it is very entertaining. Reminds me of the Mac and Photo Booth…it really gives you a chance to take the new system out of the box and start having fun with it.

flickr a day

2006-11-02T05:17:18Z

I recently imported some older albums into iPhoto and am trying to upload at least one or two photos a day to my flickr page. Feel free to have a look.

I really wanted to buy my sister’s Canon digital SLR once my condo sold but that hasn’t happened yet. I still have my trusty Canon PowerShot A80, though.

Clicky links in Terminal

2006-11-02T05:01:15Z

Hold down command and double click the URL. It’s that easy.

Thanks to a few gentlemen in #caboose for this tip.

Heroes

2006-10-27T03:39:30Z

I don’t usually get into TV shows but I’m definitely addicted to Heroes, a new show on NBC this season. It’s a lot of fun to watch and try to guess what’s going to happen next. It can be tough to deal with the cliffhangers, though. Highly recommended.

I'm available for hire

2006-09-06T19:55:28Z

I’m looking for Rails or systems work, full-time or contract. I’m currently in the Phoenix area but can do remote work and will consider moving.

Shoot me a line at dpiddy%gmail.com, where % is really @. Thanks.

Currently in the changer

2006-07-10T04:37:41Z

I changed up the CDs in my car changer (I know, I know…I’m working on an iPod connection) and thought it was a pretty rockin’ mix. Here they are:

Further Seems Forever: The Moon is Down (from back when the Dashboard Confessional guy knew how to rock)
Fairweather: Lusitania (for the longest time had the title of Favorite Album Never Heard in My Car)
Radiohead: The Bends (for people who like guitars)
Brand New: Deja Entendu (great live show (but stay out of the pit))
Engine Down: S/T (Maura Davis’ brother’s now defunct band; this album along with The Moon is Down are two of the best-drummed albums I’ve ever heard)

And there you have it. Get to rocking.

Polymorphic Combo Accessor Plugin

2006-06-29T16:14:45Z

Makes form work easier.


script/plugin install http://svn.dpiddy.net/plugins/polymorphic_combo_accessor

See the README

Rockies pitchers using video iPods to prepare

2006-06-17T05:23:12Z

As seen in this CNN article, it didn’t take long for baseball to find a use for the video iPod. I’ve heard of pitchers like Curt Schilling poring over video and notes of batters but to have video like that in the palm the pitcher’s hand is pretty cool.

It’s not just the pitchers, though. Todd Helton has every one of his hits since 1998 stored by month. That’s over 1500 videos of success he can watch any time he’s not doing so well. Seems like that’d be pretty good for a lift.