- luv-main - luv.asn.au

telstra website
by Brian May 19 Feb '12

19 Feb '12

Just trying out Telstra NextG and seeing if it resolves some of the problems I had with Three (e.g. high network charges when roaming on to Telstra). On of the first observations is that the website seems to be incompatible with Firefox, Chromium, and Android browser; in all three environments clicking the next button does nothing: https://www.my.telstra.com.au/myaccount/register Wish I could say I was surprised, but then my nose would start growing :-) Are there any workarounds? Besides get IE on a Windows box, which I assume should work? Then again, looking at the HTML, not sure how this should work under IE either, so maybe classing this as a Linux accessibility issue might be wrong? Unless there is some JavaScript that is suppose to alter this HTML to something that works. <a class="btn_blue submit" href="javascript:void(0)">Next ></a> Thanks -- Brian May <brian(a)microcomaustralia.com.au>

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btrfs -- what happens when a checksum fails on a single disk?
by Toby Corkindale 17 Feb '12

17 Feb '12

btrfs -- if you have your data stored multiply (ie. raid mirror) then if one copy goes bad, it'll resync it from the other copy. That's all well and good. Can you explain the failure modes for when a block checksum fails when you have data on a single disk? (I gather that there are both block and extent checksums, but correct me if I'm wrong) Essentially I was wondering whether you'd lose an entire file (or extent of a file) if the checksum fails, or whether you could still access the rest of the file but with just one block missing in the event of a bad sector. Cheers, Toby

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List Issues
by Andrew McGlashan 17 Feb '12

17 Feb '12

Hmmm, Strangely this list will not give a "list copy" to those that are otherwise addressed in the to or cc headers. I am seeing every email I send come back via the list okay, but those sent to me AND the list are only arriving to me as non list copies -- in this situation I would expect two emails, but I'm only getting the non-list one. I know that Google has some "issues" with sending list copies of emails to the original sender (perhaps they have changed this). Can the list manager software that LUV uses please ALSO send list copies? I don't mind getting multiple emails and for filing purposes I want ALL emails to the list to arrive with the appropriate List-Id header. Thanks. -- Kind Regards AndrewM Andrew McGlashan Broadband Solutions now including VoIP Current Land Line No: 03 9012 2102 Mobile: 04 2574 1827 Fax: 03 9012 2178 National No: 1300 85 3804 Affinity Vision Australia Pty Ltd http://www.affinityvision.com.au http://adsl2choice.net.au In Case of Emergency -- http://www.affinityvision.com.au/ice.html

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Re: RAID-1 synchronisation
by Tim Connors 15 Feb '12

15 Feb '12

On Sun, 5 Feb 2012, Daniel Pittman wrote: > > btw, when btrfs is stable/production-system-ready then the authors are > > correct - fsck won't be necessary. same as it isn't necessary on ZFS. > > they both do (or will do in the case of btrfs) continuous consistency > > checking and file-level checksumming. and the btrfs authors are right to > > focus on improving btrfs itself rather than getting too side-tracked by > > an fsck tool. > > Very much the XFS model, then. You might have an external tool that > will check or repair it, but the basic model is that the in-tree code > gets it right through everything going wrong. Just in case anyone is under the mistaken impression that ZFS is reliable and self repairing (well, I guess it is, technically), here is a status update from an Scary Devil Monastery oldtimer: Aaaaaarrrrrrggggggghhhhhhh!!!! I just lost 3 websites on my big server! Power crashed this afternoon. They were all in a ZFS file system, /z1/blogspace, but now /z1/blogspace is EMPTY! I had built them and got the blogging software running, but power failed before I could get them backed up. I wonder what else I have lost ... . (Yes, I am surprised that such an oldtimer isn't making automated backups twice a day, but he always did seem better with big-iron than these little itty bitty solaris boxen) Me, I stick with ext3/ext4 with certain "features" turned off, because they're filesystems I've never lost anything important on, unlike many others. Actually, that reminds me. This thread is hilarious - particularly Chris Mason's reply 3rd down: http://thread.gmane.org/gmane.linux.file-systems/23709 People doing fsync() (and worse, the people insisting you need to use it otherwise you're a data hater) are probably making their data more fragile. xfs? fragile. ext4 without barriers? Probably just fine, thanks very much! I can't tell any difference between speed of filesystems in practice anyway. -- Tim Connors

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btrfs and per-file COW and compression
by Chris Samuel 15 Feb '12

15 Feb '12

Hi folks, IIRC some people on luv-main have had issues using VM's with btrfs due to poor performance with its COW behaviour. Now COW is something you can disable either per mount or per-file but there wasn't really a good utility to do it per-file (a patch has been sent for chattr/lsattr but not yet merged apparently). However, a program called fileflags has been posted to linux-btrfs that lets you enable/disable both COW and compression on a per-file basis: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/15737 Be interesting to know if it does help people! cheers, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC This email may come with a PGP signature as a file. Do not panic. For more info see: http://en.wikipedia.org/wiki/OpenPGP

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Trouble with a mini-pcie wireless card
by Toby Corkindale 14 Feb '12

14 Feb '12

I built a new mini PC recently, but have had some trouble with the wifi on it. (Asus E45M1-I motherboard) The motherboard has a mini-PCIe slot which contains an Atheros Azurewave wifi card. (it comes out of the factory with this card) I can't detect the wifi card at all in Ubuntu 11.10 - it doesn't even seem to show up in the results from the lspci command. I can't see anything in the EFI BIOS about enabling or disabling the wifi nor the PCIe slots. I eventually caved and installed Windows 7 and I can't seem to see the wifi card there either, even with the official drivers installed. So I'm thinking it's not a Linux issue, but I wondered if the collective wisdom here has any ideas what the problem could be? My thoughts so far are: a) The mini-PCIe slot is broken. b) The mini-PCIe wifi card is broken. c) There's some kind of hardware "disable wifi" switch hiding on the board that I can't find :/ d) There's some kind of software "Disable wifi" feature that needs to be toggled somehow, but I have no idea where to find. What I've tried: * Removing the mini-PCIe card and reinserting it. I don't have a spare half-length mini-PCIe card lying around to swap in, nor anything else to test the wifi card in, which makes it hard. :/ (They're only $10 on ebay, so if there are no good suggestions I'll just buy one and give it a shot and at least discover if the slot works.) Do you know if mini-PCIe slots are physically compatible with real PCIe slots? Unlikely, but thought I'd ask, in case I can jam the mini board into a full slot in my desktop..

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Thunderbird problem
by Peter Ross 14 Feb '12

14 Feb '12

Hi all, sometimes (infrequent) I am using Thunderbird to send e-mail folders from one user to another. At the moment it stops after a while, with this message: The connection was refused when attempting to contact live.mozillamessaging.com. What the hack?? The setup was pristine, accounts are internal ones.. the Thunderbird does not have any messaging configured (AFAIK). Why does Thunderbird want to connect to that server? How do I stop it? Thanks for answers Peter

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cron
by Tim Connors 14 Feb '12

14 Feb '12

For such a critical system component, why is cron so devilishly stupid? 1) Hour and minute are backwards. I get bitten by this all the time, particularly on days when I had to get up too early to do software patching on a few dozen servers. 2) For that matter, all the other time fields are backwards too. Must have been written by an American. In the rest of the sane world, we start with least significant and then work out way up to most significant (or the reverse). Not go backwards and forward all over the shop. 3) All the time fields are ANDed. Except day and month. So debian needs this hack to run mdadm check on first sunday of the month: 57 0 * * 0 root if [ -x /usr/share/mdadm/checkarray ] && [ $(date +\%d) -le 7 ]; then /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi instead of this: 57 0 1-7 * 0 root if [ -x /usr/share/mdadm/checkarray ] ; then /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi You have to go to extra effort to make it this bad. Why would you possibly want the date field to be ORed with the day of week? Was vixie on powerful drugs at the time? 4) "cron reads the crontab file(s) every minute to see whether there have been changes. Therefore, any change to its schedule will take effect within one minute." No, it reads the cron files every minute, and then applies the new schedule the next minute? Ie, there's always a minimum of a 1 minute delay to a schedule update, and up to 2 minutes. Why? Why would it not just read the new times, and if there's an entry for the current minute, act upon it instead of checking whether there was a job due the next minute to apply in the next minute? Again, this requires special kind of bodgery to get wrong. Unfortunately, this crappy behaviour is well embedded in the standard operation of cron, and can't be changed because it would break the expected broken behaviour. Can we define a new standard is-not-quite-cron? This rant brought to you by yet another "/tmp/crontab.uPh6Gi/crontab":24: bad hour errors in crontab file, can't install. Do you want to retry the same edit? (y/n)" -- Tim Connors

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RE: Warranty (was RAID-1 synchronisation)
by James Harper 13 Feb '12

13 Feb '12

> Hi, > > On 11/02/2012 1:10 PM, James Harper wrote: > > "Enterprise" drives don't normally cost that much more, although looking at > the prices right now they are quite a bit more expensive at the moment from > at least one of our suppliers. > > Drive pricing was severely effected by the Thailand floods. > > There is enough price differential between standard and enterprise drives, > but the standard ones come with lesser warranty -- I think it is better to > choose enterprise ALWAYS, just due to the warranty period extension. > > If the warranty is longer, then it should follow that the drive is more reliable > and can be trusted more easily (aside from the "use" type settings). > On the subject of warranty, the laws in australia have changed for goods purchased since 1/1/2011. The manufactures warranty just represents the point where you can get your money back easily. The product must still function for a reasonable time after purchase and must be repaired or replaced if it fails within that time, although I think that responsibility falls to the party you purchased it off. The "reasonable time" bit isn't clearly defined, but if I bought a disk and it failed within 18 months I'd be contacting the place I'd bought it off, even if it only came with a 12 month warranty. No manufacturer is going to agree that their product isn't expected to last 3 years. >From http://www.accc.gov.au/content/index.phtml/itemId/1023610 "Is there a time limit on when you can use your rights? There are no specific rules about exactly how long a product or service should last. Even after a voluntary or manufacturer's warranty expires you may still be entitled to a repair, replacement or refund. This will depend on what you purchased and the nature of the problem." Disks are a bit tricky though... I'd be reluctant to return a $99 disk for repair/replacement if it was a standalone or part of a RAID1 and had my (or my customers) data easily accessible, even if the chances are it would just be sent for destruction anyway. I guess that's another advantage of RAID[56]. It's all out the window if you imported it direct from an overseas reseller of course, but that's a choice you make. OT but it's also worth noting that the phone situation is much more clearly defined. If you get a phone on a contract from a Telco, your phone is covered at least for the duration of the contract (eg if your phone breaks 18 months into a 24 month contract they have to repair or replace it). Something to keep in mind next time your telco tries to screw you over (as was the case when my mum bought a phone recently). James

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state of ZFS and btrfs (was: RAID-1 synchronisation)
by Toby Corkindale 12 Feb '12

12 Feb '12

On 05/02/12 19:13, Daniel Pittman wrote: > On Sat, Feb 4, 2012 at 23:30, Russell Coker<russell(a)coker.com.au> wrote: >> On Sun, 5 Feb 2012, Daniel Pittman<daniel(a)rimspace.net> wrote: >>> Yes, it does good. For something like RAID-5 that has enough >>> information to detect which device is wrong you can find and correct >>> problems with the system. With a RAID-1 you can know that a device is >>> returning bad data. >> >> You mean RAID-6. RAID-5 is no better than RAID-1 when it comes to determining >> which one of the disks is returning corrupt data. > > Sorry, yes, I did. I was thinking about that at the time I wrote it, > then went back and edited. Obviously, poorly. > >> On Sun, 5 Feb 2012, Daniel Pittman<daniel(a)rimspace.net> wrote: >>> Yes. This is the substantial advantage that BTRFS and ZFS have over >>> device-level RAID and LVM. The stronger checksums are useful because >>> they can be checked inline with lower I/O cost, and the intimate >>> knowledge of allocated space means you can check more quickly. Both >>> very attractive features. >> >> https://btrfs.wiki.kernel.org/ >> >> The above URL lists mirroring as "Additional features in development, I don't >> think I can use this on serious servers for a while. > > Honestly, I wouldn't touch btrfs for some time. Last I heard overhead > was still in the thirty to fifty percent range, which makes ZFS look > nimble and efficient by comparison. ZFS looks significantly better, > though it is still a little annoying to use on Linux, and > Debian/KFreeBSD is annoying enough that I never got to testing it out > seriously. I've been giving ZFS a bit of a trial run on one of my servers, because the block-based deduplication looked attractive, as did the checksumming and using an SSD as L2 cache. Unfortunately I ended up giving up -- it *seemed* pretty good on the surface, but I managed to kill the server too often. I ended up in a state where attempting to 'rm -rf' a (large) directory would cause the machine to spike up to over 100 load, and after 15+ minutes the hardware watchdog would reboot the machine because it'd become totally unresponsive, even to the console. Prior to these crashes, there'd be a bunch of log messages about kernel memory allocation failures. I'm pretty sure this was because the memory required for the dedup hash map is huge -- gigabytes per terabyte of storage. Now, if that can't fit in RAM, then ZFS should just be paging it in from disk, which is slow, but shouldn't crash the machine. However in practice it did seem to kill it :( I'm giving btrfs another go now; pity about losing the block-based dedup (which is great when you have a lot of virtual machine images), but the overhead just wasn't worth it for me. One thing I'm already struggling to find in btrfs is simply to work out how much space a snapshot is consuming! Anyone? -Toby

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