Jet lag (Mar 12 2007)


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Profile Matt Lebofsky
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Message 530530 - Posted: 12 Mar 2007, 22:50:42 UTC

It's amazing how the one hour difference is making me feel loopy. Our computers more or less survived the unexpected change in DST schedule. When I checked on Sunday morning ewen was off by an hour. Its time zone was Pacific/Tijuana, unlike the rest of our linux machines which are Pacific/Los Angeles (or somewhere else in CA). Easy fix, and nothing was harmed.

Kryten (the upload server) needed to be rebooted twice within the last 36 hours. We're working steadily towards replacing it. Don't you fret. Bruno (what will be the new upload server and then some) was stress tested all weekend, and is now currently being configured. Since it is a new OS a lot of programs need to be recompiled. Plus the new OS means upgrading to apache 2, which means no more external fastcgi servers (?!), which means I was scratching my head for a while this afternoon figuring out how to change the way we do fastcgi around here.

Before anything goes on line we still have some physical clean up to do. Jeff and I mapped out a few tasks for tomorrow, mostly involving removing some switches recently rendered pointless and rerouting some dangerously placed power cables. Eric and I also got rid of an old switch in room 329 (replaced with a one of the recently donated switches). Perhaps this old switch was causing the
headaches with Kryten?

The replica server is working great but still not on UPS yet. We're working on it. I aimed a couple more queries today at it, namly the "top hosts" page generators and the like. Those particular selects are expensive and were wreaking havoc on the main database server when too many people were trying to access the page at once. There is web cache code in place to reduce this behavior, but the slower the queries, the worse the race condition that results in multiple redundant selects hitting our database at once. Anyway, I have some test code in there and will try it out overnight. Before doing all this I was given other logic to try (late last week) to reduce the strain but this produced funny results, as some users noted in a different thread. All better now.

I need to update the server status page. I know.

- Matt

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Message 530544 - Posted: 12 Mar 2007, 23:15:14 UTC - in response to Message 530530.
Last modified: 12 Mar 2007, 23:22:26 UTC

It's amazing how the one hour difference is making me feel loopy. Our computers more or less survived the unexpected change in DST schedule. When I checked on Sunday morning ewen was off by an hour. Its time zone was Pacific/Tijuana, unlike the rest of our linux machines which are Pacific/Los Angeles (or somewhere else in CA). Easy fix, and nothing was harmed.

Kryten (the upload server) needed to be rebooted twice within the last 36 hours. We're working steadily towards replacing it. Don't you fret. Bruno (what will be the new upload server and then some) was stress tested all weekend, and is now currently being configured. Since it is a new OS a lot of programs need to be recompiled. Plus the new OS means upgrading to apache 2, which means no more external fastcgi servers (?!), which means I was scratching my head for a while this afternoon figuring out how to change the way we do fastcgi around here.

Before anything goes on line we still have some physical clean up to do. Jeff and I mapped out a few tasks for tomorrow, mostly involving removing some switches recently rendered pointless and rerouting some dangerously placed power cables. Eric and I also got rid of an old switch in room 329 (replaced with a one of the recently donated switches). Perhaps this old switch was causing the
headaches with Kryten?

The replica server is working great but still not on UPS yet. We're working on it. I aimed a couple more queries today at it, namly the "top hosts" page generators and the like. Those particular selects are expensive and were wreaking havoc on the main database server when too many people were trying to access the page at once. There is web cache code in place to reduce this behavior, but the slower the queries, the worse the race condition that results in multiple redundant selects hitting our database at once. Anyway, I have some test code in there and will try it out overnight. Before doing all this I was given other logic to try (late last week) to reduce the strain but this produced funny results, as some users noted in a different thread. All better now.

I need to update the server status page. I know.

- Matt


Good Work there Matt . . . reference was this Thread - eh?

Top 1000 Computers . . . #999 with a RAC of 0.11?

looks fine now . . .

[off topic]
> strangE notEs 'ErE . . . rEgarding Frank Zappa's Death . . .

Zappa's Death

alt . fan . frank-zappa
[back on topic]

Profile hiamps
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Message 530561 - Posted: 12 Mar 2007, 23:48:34 UTC - in response to Message 530530.

And you still find time to play guitar? Thank you.
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Metod, S56RKO
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Message 531191 - Posted: 14 Mar 2007, 10:08:53 UTC - in response to Message 530530.
Last modified: 14 Mar 2007, 10:09:46 UTC

It's amazing how the one hour difference is making me feel loopy. Our computers more or less survived the unexpected change in DST schedule. When I checked on Sunday morning ewen was off by an hour. Its time zone was Pacific/Tijuana, unlike the rest of our linux machines which are Pacific/Los Angeles (or somewhere else in CA). Easy fix, and nothing was harmed.


A question (may be to all of sysadmins ot there?): why would one want to run a decent server and set timezone to anything that has DST? System-wide that is, one can always set timezone for interactive users to whatever applies to your location. I can only guess one reason: cron jobs that process data which is tied to legal time.
I normally prefer timezone set to UTC on servers ...
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Message 531211 - Posted: 14 Mar 2007, 13:29:32 UTC - in response to Message 531191.

It's amazing how the one hour difference is making me feel loopy. Our computers more or less survived the unexpected change in DST schedule. When I checked on Sunday morning ewen was off by an hour. Its time zone was Pacific/Tijuana, unlike the rest of our linux machines which are Pacific/Los Angeles (or somewhere else in CA). Easy fix, and nothing was harmed.


A question (may be to all of sysadmins ot there?): why would one want to run a decent server and set timezone to anything that has DST? System-wide that is, one can always set timezone for interactive users to whatever applies to your location. I can only guess one reason: cron jobs that process data which is tied to legal time.
I normally prefer timezone set to UTC on servers ...


yes thats ok but in the UK we have a DST as well and in windows you can set it to change when we go forwards and backwards (linux i think is the same "but dont quote me!")so you would have the same problem.
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Message 531217 - Posted: 14 Mar 2007, 13:56:29 UTC - in response to Message 531211.
Last modified: 14 Mar 2007, 14:09:07 UTC

yes thats ok but in the UK we have a DST as well and in windows you can set it to change when we go forwards and backwards (linux i think is the same "but dont quote me!")so you would have the same problem.


In UNIX (Linux at least, I guess it's similar in other UNIXen) you can set your time zone either to UTC or GMT. There's not a lot of difference between the two apart from the fact that setting time zone to GMT means you're adhering to rules of legal time in UK (including BST) while if you set it to UTC you're adhering to UTC rules, which doesn't have any DST.

[edit]
The above is probably full of wrong information. What is proper name of timezone for UK? Hmmm ... could it be GB? On Linux time zone GMT seems to be synonym for UTC while GB changes from GMT to BST during summer:

$ TZ=Europe/London date; TZ=Europe/London date --date="20070526 12:00"
Wed Mar 14 14:06:47 GMT 2007
Sat May 26 12:00:00 BST 2007
[/edit]

Linux keeps it's system clock at UTC regardless of what the time zone setting is. Popular network time protocol also uses UTC. It observes the time zone set at boot-time when it takes time from CMOS (or whatever clock hardware in machine) if not instructed otherwise. It also converts the output according to time zone rules when some sort of output needed (eg. date or ls). You can check this following this example:

$ date; TZ=US/Pacific date
Wed Mar 14 13:54:07 UTC 2007
Wed Mar 14 06:54:07 PDT 2007

or similarly with ls.
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Message boards : Technical News : Jet lag (Mar 12 2007)

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