Roundtable

roundtable@muug.ca

2555 discussions

"un-RAIDing" a Linux P2V
by Wyatt Zacharias 01 Dec '15

01 Dec '15

So I'm attempting to virtualize one of our Redhat 5 boxes using VMWare's P2V functionality, and it's copied all the data into the VM without any trouble, but now I can't seem to get the virtual machine to boot because it's not detecting the virtualized partitions correctly. The physical system was using LVM on top of dm-raid to local disks. When VMWare virtualized the disks, it created a single disk, and copied the LVM layout onto it, so I think what's happening is on boot, the system is looking for the RAID disks and can't find them. When I try to boot it, it says that it can't find the logical volumes and goes into a kernel panic. I've booted with a rescue disk, and when I run a pvscan on the new virtual disk, all the volumes are there and can be mounted, so the problem must be that the system isn't looking for the volumes in the right place. I've tried changing the root device to /dev/sda in the device.map comfig file, and I rebuilt the initrd file with both the --force-lvm-probe and --omit-raid-modules and it still loads dm-raid on boot. So how do I get the system to completely forget about RAID, and boot off the new virtual disk? Is there a RAID config somewhere that I'm missing? -- Wyatt Zacharias

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O'Reilly 60% off is back
by Trevor Cordes 28 Nov '15

28 Nov '15

It's back, O'Reilly's periodic (twice yearly?) 60% off sale on *all* e-books and vids (but not print books). You have to spend $100 (US$) to get the 60%, otherwise it's only 50%. Based on past experience they never go cheaper than 60% off. I'm still waiting for blow-out deals on print, but they never come... http://shop.oreilly.com/category/deals/cyber-monday.do Ends Dec 1, 5am PT.

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Amazon price jacking
by Trevor Cordes 19 Nov '15

19 Nov '15

Thought I'd drop the group a quick observation regarding Amazon. I'm always on the eye out for O'Reilly books and keep an eye on Amazon pricing (both new and used) for the books in my want-list. A strange thing just happened I haven't noticed before. In the last .5 to 1.5 weeks Amazon.ca jacked up the "new, sold by Amazon" prices on nearly all the O'Reilly titles I am watching (some recent titles, some ancient) about 20%! In that time the CA$ went down by at most 2%. My guess is it's one of three things: 1. Jacking prices up for Christmas because they can get away with it. 2. Jacking prices up before Black Friday/Monday(whatever) so they can claim their new prices are "sales" when in fact they are the prices from 2 weeks ago! 3. They held back the CA$ pressure as long as they could then finally broke and jacked them up 20% in one go. #3 seems unlikely because their prices fluctuate nearly every day, probably on the exchange rate. Indigo prices seem to have followed Amazon, so it looks like this is a common book store tactic. If you don't need a book for a present, might want to wait until January to buy as prices should drop by 20% again. Even more if the CA$ ever recovers.

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WTB: DDR2 ECC UNB 2GB
by Trevor Cordes 18 Nov '15

18 Nov '15

Hi! If anyone happens to have any (relatively) obsolete DDR2 ECC modules kicking around, I'd like to buy 2 or 4 sticks. I need unbuffered, unregistered, ECC, DDR2, 667 or 800 MHz, normal mobo size (not sodimm). Note, if you don't know if your RAM is ECC, it probably isn't (ECC is "kind of server"). Note also that buffered/reg'd is useless to me too. Email me privately. Thanks!

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metadata *is* in the inode
by Trevor Cordes 16 Nov '15

16 Nov '15

At the meeting last week we were discussing inodes and metadata, and where metadata is actually stored. I double-checked what I was saying, just to make sure, and it turns out I was correct: many modern fs's (like ext4) store some metadata in the inode. This is because ext4 has a 256 byte inode by default but only needs about half of that to store "normal" inode data. Thus, "the remaining space after the ext4_inode structure is normally used to hold extended attributes". That would include capabilities (along with selinux stuff, etc), I would assume. Of course, if your metadata is over about 100 bytes then the fs will need to allocate other blocks for the metadata. I'm sure there's a way to test all this with just ls, df and setcap or selinux. Further, looks like there's a patch called "Inline data" (doesn't seem to be in my kernel, perhaps not mature yet) that allows *data* to be put in the empty space. That would allow tiny (100 byte) files (or even directories with few files?) to use no blocks at all! They'd also load super fast. I swear that I've seen that behavior on my systems, but I'm not sure which, perhaps my XFS fs. Perhaps if your fs is full of tons of tiny files you could gain huge advantage by setting your inode size even higher (at fs creation time only)! source: https://lwn.net/Articles/469805/

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MWUG archives being given away
by Colin Stanners 11 Nov '15

11 Nov '15

A co-worker found this, asked me if I am interested in this piece of Winnipeg computer history but I have too much junk / too many other projects going on already. http://www.kijiji.ca/v-other-computer-products/winnipeg/mwug-archives/11031…

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One of our members in the news
by Bill Reid 08 Nov '15

08 Nov '15

Alan Moulding in the Metro News: http://www.metronews.ca/news/winnipeg/2015/11/06/winnipeg_s-biggest-music-f…

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LVM import question
by Kevin McGregor 03 Nov '15

03 Nov '15

I would like to be able to temporarily move a disk from one Linux system to another. The disk has a complete LVM2 volume group on it which I would like to mount on the second system. However, I may or may not be able to mark the volume group as "exported". Is there any way to import a volume group which isn't marked as "exported"? Or to use the destination system to mark it as such? Background: I've been tasked with creating a Linux VM (Virtual Machine) with ClamAV on it which can scan other Linux VM disks. To do that I assumed I'd shut down the target system and mount its disks on the scanning VM, do the scan, then remove the target disks from the scanning VM. Is there a better way? Kevin

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System accounting misbehaviour in MacOS X 10.10 (Yosemite)
by Gilbert E. Detillieux 03 Nov '15

03 Nov '15

After Adam's mini-presentation on classic UNIX system accounting (sa, lastcomm) at the October meeting, I decided to set it up on various Linux and MacOS X systems I maintain. I came across a curious issue under MacOS X, where timestamps were correct for root processes, but wrong for everyone else. Turns out, I'm not alone in noticing this... http://unix.stackexchange.com/questions/206815/system-accounting-misbehavio… I haven't found any solution to this, nor anything from Apple documenting this. I imagine this is not likely to be a priority issue for anyone, though. -- Manitoba UNIX User Group E-mail: <gedetil(a)muug.mb.ca> c/o Gilbert E. Detillieux Web: http://www.muug.mb.ca/ University of Manitoba Phone: (204)474-8161 Winnipeg MB CANADA R3T 2N2 Fax: (204)474-7609

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MUUG Meeting, Nov 10, 7:30pm -- Elasticsearch, Logstash, and Kibana
by Gilbert E. Detillieux 03 Nov '15

03 Nov '15

The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting on Tuesday, November 10. The meeting topic for this month is as follows: Elasticsearch, Logstash, and Kibana Robert Keizer will be doing a presentation on Elasticsearch, Logstash, and Kibana. The presentation will focus on running these systems in a production environment. Elasticsearch is a highly available NoSQL distributed database which is primarily used for real-time and deep searching. When used in conjunction, these systems provide a very robust and feature-complete solution for enterprise log management. Rob will go through setting up and installing all three systems, as well as provide an overview and example of these systems. RTFM For this month's RTFM, Gilbert Detillieux will talk about the getcap(8) and setcap(8) commands, used to control Linux capabilities(7) as an alternative to using setuid-root binaries. This provides a safer way of allowing unprivileged users to execute operations normally requiring root permission. AGM Plus, this month's meeting is the MUUG annual general meeting, which included the election of the MUUG board of directors for the 2015-2016 year (which will be by acclamation). There is also a notice of motion to ammend the MUUG by-laws. 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 *NEW* meeting location for this month: *Room 1M28* Manitoba Hall, University of Winnipeg, entrance on Ellice Ave. between Spence St. and Balmoral St. Parking is available on the surrounding streets and in the lots on nearby streets. Look for signage once you're at the building, or ask a security guard. ****************************************************************** 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 -- Manitoba UNIX User Group E-mail: <gedetil(a)muug.mb.ca> c/o Gilbert E. Detillieux Web: http://www.muug.mb.ca/ University of Manitoba Phone: (204)474-8161 Winnipeg MB CANADA R3T 2N2 Fax: (204)474-7609

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