- luv-main - luv.asn.au

Re: outage
by Anthony 13 Sep '16

13 Sep '16

On Fri, Sep 9, 2016 at 10:25 PM, Russell Coker via luv-main < luv-main(a)luv.asn.au> wrote: > The LUV server has just been down for a few hours. > > It all started a couple of weeks ago when I wrote a Mon plugin for running > lm- > ... > Now I think that everything is fine. Email me off-list if you notice any > problems. +1 on the excellent report. <rant> Better than the crap one usually sees from commercial services "There's an issue affecting a really tiny PERCENTAGE of our HUGE customer base" ... "The issue is being examined" ... "The issue has been resolved, we value your custom, your call is important to us, batteries not included, free unicorn to the first 50 callers, we are AWESOME!" It's almost worthless getting service updates from some commercial services for all the useless waffle they usually have </rant>

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outage
by Russell Coker 10 Sep '16

10 Sep '16

The LUV server has just been down for a few hours. It all started a couple of weeks ago when I wrote a Mon plugin for running lm- sensors to monitor system temperature. When I installed that on every system that matters to me I noticed that the hardware that runs the LUV server was reporting a CPU temperature greater than the recommended maximum. It isn't necessarily a bad thing for a CPU to run above the recommended maximum (80C in this case) for a while as long as it is well clear of the critical temperature (in this case 100C) but running 24*7 above the maximum temperature is obviously a bad thing. I changed the configuration of BOINC (as described in a recent LUV lecture) to use less CPU time and the temperature went down to ~72C. Then over about a week the temperature slowly increased while the system load stayed the same. This indicated some sort of system cooling failure that appeared to be getting worse. The man who owns the hardware reported a system fault to Hetzner (the hosting company). They put new thermal paste on the CPU and cleaned out some dust. Then the system didn't boot. After some investigation (including some delay due to the Hetzner KVM not working) it turned out that I had made a mistake in not removing a /etc/fstab line for a filesystem I had removed months ago and this had made the system halt the boot and prompt for a sysadmin login. To prevent this happening in future I added the mount option x-systemd.automount to all filesystems apart from root, this means that systemd will use it's automount facility and not delay system startup if a filesystem can't be mounted. If this problem happens again I will be able to ssh in as root to fix it. As the system hadn't been rebooted since early this year there were some kernel fixes to apply. I don't think there was anything critical for our use but as we had already got some downtime it made sense to get other things done. I upgraded the kernel and then the system wouldn't boot again. The physical hardware running the LUV server was the last system I run that's still using Xen. When I got it to boot again (I can't remember the exact problem there) I couldn't get it to run Xen. I then purged Xen and installed KVM. It took another 15 minutes to set up KVM but that's probably less time than would have taken to debug Xen and gave the added benefit that I'm no longer using Xen! Now I think that everything is fine. Email me off-list if you notice any problems. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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GMANE acquired by Yomura, rebuild in progress
by Chris Samuel 07 Sep '16

07 Sep '16

Hi folks, For those who've been following the GMANE shutdown it turns out that it was acquired by Yomura (the parent company of Delimiter) in mid-August and is going through a rebuild. About page which mentions Yomura & Delimiter: http://gmane.org/about/ Blog with some information about the takeover: http://home.gmane.org/2016/08/29/next-steps-gmane/ Update that traffic has started to flow again: http://home.gmane.org/2016/09/06/reboot-v1/ See via this LWN update: https://lwn.net/Articles/699704/ cheers, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC

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Mounting A Samsung Phone
by David Zuccaro 31 Aug '16

31 Aug '16

Good morning good people, When I mount my samsung phone in debian linux, which directory (starting from root) can I access the files on it from the command line? I'm trying to find and copy a mms video file off it. Sorry if that's worded awkwardly, hope it makes sense. Best regards to all, David Zuccaro

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Hardware for kids
by Russell Coker 30 Aug '16

30 Aug '16

I've been collecting hardware for Wooranna Park Primary (which runs a Coder Dojo as described in a LUV lecture last year). They are after things that the kids can fix up and learn from. PCs and Laptops that they can install Linux on and random hardware they can play with. If you have stuff that may be suitable and can bring it to a LUV meeting let me know off list. -- Sent from my Nexus 6P with K-9 Mail.

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Compose Melbourne, functional-programming conference + unconference, Monday, Tuesday
by Les Kitchen (LUV) 27 Aug '16

27 Aug '16

We're running a functional-programming event, Compose Melbourne, on Monday and Tuesday this coming week at RMIT in the City: http://www.composeconference.org/ Since it's a local, community-based technical event, and there are strong links between functional programming and FOSS, I thought it might be of interest to LUV members. Day 1, Monday, is a conference with speakers and paid registration. Day 2, Tuesday, we'll be running free workshops, including one on Haskell for Beginners. While the workshops are free, you still need to register, and possibly install software on your laptop ahead of time. More generally, Tuesday is a free unconference, a chance for people to get together informally and share their interest in functional programming. So, if you'd like to learn more about functional programming, and meet people also interested in functional programming, then come along to Compose Melbourne. Sorry for short notice on this. — Smiles, Les.

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Happy 25th birthday Linux!
by Andrew Pam 25 Aug '16

25 Aug '16

"On August 25, 1991, an obscure student in Finland named Linus Benedict Torvalds posted a message to the comp.os.minix Usenet newsgroup saying that he was working on a free operating system as a project to learn about the x86 architecture. He cannot possibly have known that he was launching a project that would change the computing industry in fundamental ways. Twenty-five years later, it is fair to say that none of us foresaw where Linux would go — a lesson that should be taken to heart when trying to imagine where it might go from here." https://lwn.net/SubscriberLink/698042/a58a7e353224ef3d/ And thanks to LWN.net for their consistently excellent coverage. Share and enjoy, Andrew

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Cheap Home Cloud ~ Raspberry Pi + USB Drives
by Piers Rowan 21 Aug '16

21 Aug '16

Friday random semi-serious question; Like many people I have too much data some work, some create some family, some other...etc. I have some on some backup USB drives that I have never gone back to and also a few unplugged HDD's in the tower (I can't remember even why). I don't really want to go and buy something (or pay for data of cloud storage) but I thought I might do something with the stuff I have lying around. Does anyone know if this is possible: - Set up a Raspberry Pi server which exposes a single file system - Link it to the USB HDD's of different sizes that I have lying around - I save my data to it for backups - The data is placed redundantly over the drives so it can recover from one [or more] dying Bonus point: - I can remove one of the drives and access the data on it directly (so it is FAT32 not Linux RAID) Any ideas? GFS? Cheers P

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MySQL - JOIN's, INDEX's and/vs seperate quiries
by Piers Rowan 21 Aug '16

21 Aug '16

Hi There, I am working on a query that I have used both joins and sub queries to try to make into something efficient. I have used the EXPLAIN command to make sure I am taking advantage of indexes and I have added them where they are lacking. The structure of the query looks like this: People_table <--- where the rows I want to show on the screen come from (name, address, etc) - Notes <--- One Person may have many notes, using date range search, also using INT search, and this is using FULLTEXT IN BOOLEAN MODE searching - Profile <--- This is a single text column, this is using FULLTEXT IN BOOLEAN MODE searching - People <--- Filtering by state, country, status, other ENUM / INT flags I have tried (JOINS): SELECT FROM People JOIN Notes JOIN Profile WHERE People Criteria AND Notes Criteria AND Profile Criteria And tried (SUB QUERIES) SELECT FROM People WHERE People.id IN (SELECT P.id FROM NOTES WHERE Notes Criteria AND Pid IN (SELECT P.id FROM Profile WHERE Profile Criteria AND P.id IN (SELECT P.id FROM People WHERE People Criteria) So far I have killed the process after a few minutes as it just takes too long. I noticed temporary tables were being created so I enlarge the join buffer pool in my.cnf which cleared some of the feedback from the EXPLAIN. (...and tried a few others...). Then there is this: - I can do the 3 queries in PHP independently and then use this to get a list of ID's at the application layer to send a 4th query to get the results and it only takes a few seconds. A FEW SECONDS! Questions: - My gut tells me that this should be most efficiently handled at the application layer - How can 3 sub queries take more time than 3 independent queries? - The "People Criteria" is all ENUMS and INT's which are indexed - I though by making this the inner most subquery that it would filter out the most rows before the slower FULLTEXT queries kicked in - is this correct? - JOINS vs SUBQUERIES - is there are "rule"? Does this "rule" get pushed aside when real world testing proves the user experience at the application layer is better by combining multiple SQL quires as opposed to handing it off to the MySQL server? Ideas? Thanks in advance. Cheers P

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old SATA disks
by Russell Coker 19 Aug '16

19 Aug '16

There seems to be an ongoing demand for SATA disks from the hardware library. Does anyone have any to donate? Even 80G disks get taken. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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