Roundtable June 2010

roundtable@muug.ca

13 participants
11 discussions

restarting a process via crontab?
by athompso＠athompso.net 14 Jun '10

14 Jun '10

My server panics occasionally (bad RAM that I haven't replaced yet - it's ECC but one bank occasionally hits an uncorrectable multi-bit error), which of course leaves various state files laying around on disk without the processes to match them. In particular, fetchmail(1) is causing me problems; there's a ~/.fetchmail.pid file that's supposed to contain the PID of the running fetchmail daemon. It has to run (well, I *want* it to run) as me, not as root, so starting it from init isn't a good solution. I'd also like it to be recover gracefully if I have to kill it (or it crashes due to a bug), also contraindicating the obvious rc.local solution. So far, the best solution I've come up with is a crontab entry (for me, not root): 0 * * * * if [ -f /home/athompso/.fetchmail.pid ];then read FP</home/athompso/.fetchmail.pid;if [ -d /proc/$FP -a -r /proc/$FP/exe ];then BIN=$(stat -c %N /proc/$FP/exe);BIN="${BIN#*-> }";BIN="${BIN#\`}";BIN="${BIN%\'}";BIN=$(basename "${BIN}");if [ "$BIN" == "fetchmail" ];then exit 0;fi;fi;fi;fetchmail (or, more readably:) if [ -f /home/athompso/.fetchmail.pid ] then read FP < /home/athompso/.fetchmail.pid if [ -d /proc/$FP -a -r /proc/$FP/exe ] then BIN=$(stat -c %N /proc/$FP/exe) BIN="${BIN#*-> }" BIN="${BIN#\`}" BIN="${BIN%\'}" BIN=$(basename "${BIN}") if [ "$BIN" == "fetchmail" ] then exit 0 fi fi fi fetchmail I particularly hate the method of extracting the imagename for a given PID, but haven't come up with anything better yet. Suggestions gratefully appreciated. Or even a better way of doing this altogether; this feels like a terrible hack - it works, but doesn't seem elegant. FYI: I decided against using sed(1) to parse the output because doing it this way saves two fork(2)s and one exec(2). I know I don't need to worry about efficiency on a dual-Xeon server, but I'm trying to stay in the habit because I'm also working on 200MHz ARM5 platforms where it does matter. (And who ever thought putting the output of stat(1) in typographical-style quotes would be a good idea???) Thanks for any suggestions, -Adam

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D-Link DIR-825 dual-band 802.11N 5xGigE runs DD-WRT, for around $150
by athompso＠athompso.net 13 Jun '10

13 Jun '10

Further to my comments at the last meeting, I was pleasantly surprised when I bought a D-Link DIR-825 and discovered it can run DD-WRT. This is a *simultaneous* dual-band (i.e. two radios, one at 2.4GHz, one at 5GHz) 802.11N router with 5 GigE ports, a USB port, two antennas, and the usual array of activity lights on the front. There is a beta build of DD-WRT that runs on this unit (and thus presumably OpenWRT will also support it soon if not already). Range & performance are OK but not great. The price, however, is impressive: you can typically find it online (in Canada) for under $150. If it were a $250 unit, it would be utterly unremarkable (aside from being one of the first dual-radio models to run DD-WRT) but considering that you can still regularly find 802.11G and single-band 802.11N routers for over $150, that makes it impressive - for now. With the stock D-Link firmware, the USB port can be used for (apparently) *any* device whatsoever, and includes software to remotely connect a Windows PC to the port. Not sure how they've done this, but I'm told it should work for any USB device (subject to bandwidth limitations, of course - USB2.0 is still faster than 802.11N). DD-WRT can expose USB storage devices and (I think) printers; so you do lose something compared to the factory firmware. Flashing DD-WRT onto the device requires TFTP while putting the device into disaster-recovery mode; it was harder to find the instructions online than to actually do it. Also see CNet's review here: http://reviews.cnet.com/routers/d-link-xtreme-n/4505-3319_7-33246906.html#c… -Adam

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Re: [RndTbl] D-Link DIR-825 dual-band 802.11N 5xGigE runs DD-WRT, for around $150
by Adam Thompson 13 Jun '10

13 Jun '10

Yes, both antennas are the standard consumer-grade-router connector. In fact, you have to screw them on yourself when you unpack it :). Not sure how directional antennae play with N's beam-forming-ish tech though. -Adam

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Temperature/Humidty
by Dan Keizer 11 Jun '10

11 Jun '10

One of the questions at the muug meeting today was about temperature and humidity readings/monitoring. The 1-wire devices are quite easy to use .. there are a few links I've saved from prior here: http://delicious.com/ve4drk/1-wire -- they're about a year or so old ... an interesting take is using the owfs (http://owfs.org/) with openWRT ( http://openwrt.org/ ):-) yes -- you know it can be done :-) I know another local who has used these .. he has a nice display and info on how to do it .. it is: http://www2.ertyu.org/temp/conditions.php Dan.

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Desperate plea for help
by Kevin McGregor 07 Jun '10

07 Jun '10

I've got a HP ProLiant server running OpenFiler, and due to errors on my part, the SCSI drives got rearranged. Now the HP 6400 RAID controller complains that an "unsupported drive rearrangement has been attempted", and the logical volume is missing. Is there any way to recover the correct order of drives in the drive bay? It is a test server, so technically no big deal, but you know how it is with "test" servers... It would be pretty annoying to lose all the data. I've tried booting the 8.30 SmartStart and using the ADU/ACU utility, but it doesn't seem to show anything useful for this. It shows the controller and all drives being "uninitialized", not just being out of order. The Option ROM utility also doesn't show anything. Suggestions, aside from "use software RAID next time"? Kevin

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Replacement Shuttle PSU PC35I2402.
by Sean Cody 07 Jun '10

07 Jun '10

Anyone know of any decent place to find a replacement PSU for a Shuttle box. PSU part number is PC35I2402. It is probably not worth replacing though if there are 'off brand' options I wouldn't mind knowing a few places to search. -- Sean

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Fwd: USENIX WebApps '10 Registration Now Open
by Gilbert E. Detillieux 07 Jun '10

07 Jun '10

FYI... -------- Original Message -------- Subject: USENIX WebApps '10 Registration Now Open Date: Mon, 19 Apr 2010 11:20:33 -0700 From: Lionel Garth Jones <lgj(a)usenix.org> To: info(a)muug.mb.ca, gedetil(a)muug.mb.ca You're invited to join us in Boston, June 23-24, 2010, for the first USENIX Conference on Web Application Development. WebApps '10 is a new technical conference designed to bring together experts in all aspects of developing and deploying Web applications. Web-based applications are revolutionizing both the features that can be delivered and the technologies for developing and deploying applications. They also involve a diverse collection of issues and technologies. Take advantage of this new opportunity for interaction and synergy across these areas. The program includes: * Invited talks by industry leaders including Adam de Boor, Google, on "Gmail: Past, Present, and Future" * Refereed papers on a variety of topics such as new approaches to Web frameworks, techniques for giving users control over their Web data, better ways of managing Ajax and Javascript, and a variety of security issues ranging from better CAPTCHAs to information flow tracking. * A Poster Session and Happy Hour held jointly with USENIX ATC '10. The poster session provides a great way to let other people know about your work and to get useful feedback from the community. Submissions are due on June 13, 2010. * Work-in-Progress Reports. If you have work you would like to share, a controversial opinion, or a cool idea that's not quite ready for publication, submit a WiP by June 13, 2010. Find out more about the posters and WiPs at: http://www.usenix.org/events/webapps10/posters_wips.html WebApps '10 is part of the USENIX Federated Conferences Week. Not only do you get a 2-day conference program filled with the latest research, but you'll also have additional opportunities to mingle with colleagues and leading experts in the combined Birds-of-a-Feather sessions (BoFs) and at the various evening social events, vendor BoFs, and receptions. Your WebApps '10 registration gets you into all the ConfWeek events happening those days: tutorials, talks, workshops--you name it. Plus, registration packages offer expanded discounts. The more days you attend, the more you save! http://www.usenix.org/confweek10 The full WebApps '10 program is available at http://www.usenix.org/webapps10/proga Register by June 7, 2010, for the greatest savings. * Additional registration discounts are available! Discount types include hardship, government, and non-profit: http://www.usenix.org/events/confweek10/discounts.html * Help spread the word! http://www.usenix.org/events/webapps10/promote.html I look forward to seeing you in Boston! Sincerely, John Ousterhout, Stanford University WebApps '10 Program Chair webapps10chair(a)usenix.org ------------------------------------------------------------------------ USENIX Conference on Web Application Development (WebApps '10) June 23-24, 2010, Boston, MA http://www.usenix.org/webapps10/proga http://www.usenix.org/confweek10 Poster and WiPs Submissions Deadline: May 27, 2010 Early Bird Registration Deadline: June 7, 2010 ------------------------------------------------------------------------

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looking for a MCSE manual/book
by Kat 03 Jun '10

03 Jun '10

Designing a Microsoft Windows Server 2003 Active Directory and Network Infrastructure (2282A) isbn 0758076851 Does anyone have a copy to lend or sell to me? Thanks ------------------------------------------------------------ Katherine Scrupa Network Technology CCNA student, RRC

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Humble Indie Bundle
by Sean Cody 03 Jun '10

03 Jun '10

One thing missing from the newsletter article was a link to more information about the project. Here you are! http://infiniteammo.ca/blog/aquaria-source-released/ Alec is a really cool guy and very open about his work. -- Sean

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MUUG Meeting, June 8, 7:30pm -- IPCop
by gedetil＠cs.umanitoba.ca 01 Jun '10

01 Jun '10

The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting on Tuesday, June 8. The meeting topic for this month is as follows: IPCop IPCop is an open source Linux distribution that turns an old (or new) PC into a stateful firewall. IPCop is geared towards home and SOHO users and offers services such as DHCP server, HTTP proxy, IDS and VPN server, which are all fully configurable through an easy-to-use web interface. IPCop has very low hardware requirements. In this presentation, Jonas Lippuner will show how to install IPCop on an ordinary SD card and a Mini-ITX board. Before the break, as this month's RTFM topic, Adam Thompson will speak about the awk(1) command. The group holds its general meetings at 7:30pm on the second Tuesday of every month from September to June. (There are no meetings in July and August.) Meetings are open to the general public; you don't have to be a MUUG member to attend. ********************************************************************** Please note our meeting location: The IBM offices, at 400 Ellice Ave. (between Edmonton and Kennedy). When you arrive, you will have to sign in at the reception desk, and then wait for someone to take you (in groups) to the meeting room. Please try to arrive by about 7:15pm, so the meeting can start promptly at 7:30pm. Don't be late, or you may not get in. (But don't come too early either, since security may not be there to let you in before 7:15 or so.) Non-members may be required to show photo ID at the security desk. Limited parking is available for free on the street, either on Ellice Ave. or on some of the intersecting streets. Indoor parking is also available nearby, at Portage Place, for $5.00 for the evening. Bicycle parking is available in a bike rack under video surveillance located behind the building on Webb Place. ********************************************************************** For more information about MUUG, and its monthly meetings, check out their Web server: http://www.muug.mb.ca/ Help us promote this month's meeting, by putting this poster up on your workplace bulletin board or other suitable public message board: http://www.muug.mb.ca/meetings/MUUGmeeting.pdf -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.mb.ca> Manitoba UNIX User Group Web: http://www.muug.mb.ca/ PO Box 130 St-Boniface Phone: (204)474-8161 Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609

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Roundtable June 2010