Monday Nov 10, 2008

Disaster Recovery in Solaris

Mike La Spina, an engineer in Canada has been a member of my virtual team for about 6 months now. Mike is a great representative of the Open Solaris community, a strong advocate for quality (he doesn't really let me get away with anything) and a voice of reason when it comes to VMware, iSCSI and of course Thumpers. He connected with me in an effort to get me to fix a bug. We fixed it, he continues to suggest ways for us together, and that, to me at least, means team work.

Recently Mike contacted me about his DR plan, and I asked him to make sure he pointed me towards the blog when he published. Mike just posted a day or two ago and it is a great read. I would encourage you to take a look at it. Mike continues to drive as a tireless ambassador for Solaris and iSCSI and ZFS. All cool stuff.

Provisioning Disaster Recovery with ZFS, iSCSI and VMware


Wednesday Aug 06, 2008

Getting there

14:46:53.401 Starting RD=run1; I/O rate: (vdblite); Elapsed: 60 seconds.
For loops: xfersize=524288 threads=4

 interval                            i/o         MB/sec   bytes    read       resp    resp       resp       cpu%      cpu%
                                        rate       1024\*\*2     i/o     pct         time    max       stddev   sys+usr    sys
14:47:05.071         1    1861.87   930.94  524288 100.00    8.589  22.702    1.302    44.0         43.6
14:47:14.030         2    1863.34   931.67  524288 100.00    8.586  36.584    1.272    44.6         44.0
14:47:24.026         3    1863.05   931.53  524288 100.00    8.585  35.810    1.192    43.9         43.3
14:47:34.026         4    1862.25   931.12  524288 100.00    8.586  25.890    1.293    44.3         43.8
14:47:44.027         5    1864.35   932.18  524288 100.00    8.579  28.986    1.126    44.0         43.6
14:47:54.024         6    1858.23   929.12  524288 100.00    8.607  65.024    1.710    44.6         43.0

Wednesday Jul 02, 2008

Multipathing for Tape

It was a dark and stormy night, the back up windows opened and shut with the regularity of a 90 year old pensioner's clacking of teeth as he snored with the flem filled nervousness of old age and incontinence. The data flowed from the backing store to fixed content archives like a humpback whale strains plankton. The administrator anxiously clacked her gum back and fourth against the two teeth she had recently had crowned with a couple of diamonds (one shaped like an "i" the other clearly an "o"...some of the geeks at work thought it was a one and a zero, but, they don't understand IO) as she watched the progress of her back up. All of a sudden there was a rigid silence as the status window showed zero throughput and the tortured silent scream of failed IOs bounced off the ear buds of the administrator. With manic obsessiveness the administrator chanted her mantra "If an IO fails to complete, is it ever an IO?" and she anxiously counted off the seconds before the back up timed out. ....Over and over again she chanted her mantra as the digital clocked ticked with the slowness and regularity of a clock:

7..8..9..."...fails to complete..." 17...18....19... "is it ever an IO?"....28...29... (occasionally she changed her mantra to "I think I can I think I can" as she took power hits of her RedBull) 47...48...49... And then, with the almost ecstatic relief one feels as a particularly large boil is lanced, the IO kicked back in down the alternate path and the back up proceeded. 

So, with a rather shameless head nod towards the "The Bulwer-Lytton Fiction Contest" I announce that we have integrated multipathing for tape into Solaris build 93. This is the culmination of a lot of work in both the ST driver as well as MPxIO. In particular, we have solved the problem of logical block addressing and error recovery as well as true multi-pathing to multi ported tape drives. Additionally, this is a platform for innovation as well. Now that we have highly available tape back up windows that are natively part of the Solaris operating system (you could do some of this before with FCP2 Error recovery, but it wouldn't help with a bad HBA or cable) we can look at bus saturation so we can attempt to drive down back up times.

A strong head nod towards our experts in tape and MPxIO. Well done Randy and Wayne

Friday Jun 13, 2008

Playing to the level of desire

Last night I played a game of hockey against an all girls team. I had a bad feeling when I walked into my locker room and the captain announced that we were going to "take it easy" tonight. Three passes in the zone, no break aways and all that stuff. I was truly aghast and then I heard it was due to us playing an all girls team.

I totally disagree with the philosophy that you play a different game depending on your perception of the competition, unless it is to change the game up in order to win or play better. Dumbing down our game is insulting, not what I signed up for, doesn't do anything but fuel misogynistic tendencies and frankly, makes the other team worse. Will you play as hard as you can if you recognize that the other guy (gal) is just screwing around? Nope.

So, I played hard. I gave my best efforts against the team I played with, and they played hard. The goalie (my buddy) taught them how to check a huge guy and get away with it. He applied his stick in places that he shouldn't have. I ended up getting boarded (hard) by someone that was a foot shorter and 100 Lbs smaller. Good for her. I had a ball and I was a human pinball. (Another point, what ref is going to call boarding on some one I could bench press?) They had a break away on me because I over skated and lost the puck. If I was taking it easy, they never would have had the break away.

It was hockey, they played hard and I honored them by playing my best. There is no shame in defeat. There is only shame in not playing or trying. Play your best game. Always. You can teach and you can make them better players by playing a good clean game and playing it honestly. I think that is life too. People raise to the level of expectation and to their level of desire. 

This seems so clear and so simple to me.  

Wednesday Jun 11, 2008

COMSTAR PR

The COMSTAR press is starting to roll out and it is very cool. My team has worked on COMSTAR for more than a year, and, people from Roger Dong's team and of course our test resources and our docs folks have spent a lot of energy making the project and making it successful. Lynn blogs about it here. I expect a fair bit of press over the next few weeks. Deirdre' helped us get the campaign rolling and it is all staring to come together!  My very first Chinese blog was about COMSTAR.

I need a code review

Folks,

I need a code review. Randy, one of my whiz developers is ready to integrate his MPxIO for tape changes in build 93. This is a cool project and pretty bleeding edge. Great work and we need a code review. C'mon... Give a guy some help!

http://cr.opensolaris.org/~rralphs/review/

Best code reviewer gets a gift package from me. Cool Solaris stuff. I decide who the best code reviewer is. My decision is final and can not be swayed unless the review is delivered on the hood of a brand new car. (OK, minivan, I have lots of kids now..)

Seriously, help a guy out. Heck, post the review in my comments section... Just make sure you include your email address...

Dan

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