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Funky LVM hack we talked about...
by Tim Keller Sept. 18, 2008

Sept. 18, 2008

Hey Gang, For those of you at the meeting who don't remember, Kevin had a 32GB flash disk that had a controller that had a built in understanding of FAT32. Thus formatting it as any other file system would work until you actually wrote to it then it would go insane. I postulated that one way to solve this would be to use LVM or MD, however when we tried this I hit a road block in that pvcreate won't let you pvcreate a regular old file, you need a device file, the same thing with MD. I finally managed to get it to work without having to hand add any devices into /dev... here's how... For my testing I created 4 100MB files using the command: dd if=/dev/zero of=part[1-4] bs=1024k count=100 This is what Kevin would need to do to on his flash drive... 1. Create 16, 2GB files on the flash drive named part[1-16] 2. Create loopback to file mappings using the command "losetup /dev/loop1 part1", repeat for all devices Also note, with this you could setup loopback encryption on these devices... If you suddenly find yourself without a loopback device issue the command in /dev "./MAKEDEV loop" However, I think udev will probably take care of it behind the scenes. 3. pvcreate /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 ... 4. vgcreate vgHACK /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 ... At this point if you issue a "vgdisplay" you should see how many (PE) physical extents you have. 5. lvcreate -n volume_name -l num_of_extends vgHACK If you use -L you can specify 300M, etc. Also you can specify how many stripes you want the data to be written in, which is handy if your 16 devices were on seperate disk controllers... Also you don't have to use all the extends in one logical volume, you could create lots of little volumes. 6. mkfs.ext3 /dev/vgHACK/volume_name 7. mount filesystem, sit back in bemusement that linux gives you the flexibility to do such things. Now... while were at it, if instead of LVM, if you wanted to use MD, this is what you'd do. If you have the lvm stuff from above, unmount the filesystem and issue a vgremove vgHACK it'll warn about active volumes, blah, blah... This command will take loop1,loop2,loop3,loop4 and put them into a 4 member RAID0 with no spare. mdadm -C /dev/md0 -l 0 -n 4 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 This command will create a raid5 out of the four devices without a spare. mdadm -C /dev/md0 -l 0 -n 4 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 It'll go off and build the array, now just format and mount and you're set to go. cat /proc/mdstat to see what it's upto. I was thinking of other insane things that Kevin can do with his 3 32GB flash disks. He could create 3 logical volumes each containing 16 members and then create an raid5 MD device using the logical volume members... He could create 3 16 member raid0's and then create a raid 5 out of them. He could install ZFS on top of fuse and then put all 48 devices into a zpool... I'll stop here, but I'm sure others have some even demented/funny ideas... Enjoy! Tim. -- I am weary of the allegiances of any politician who refers to their constituents as "consumers".

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REMINDER: Upcoming Meeting on Wednesday
by Andy Stewart Sept. 16, 2008

Sept. 16, 2008

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 HI gang, The next WLUG meeting will be on Wednesday, September 17th, 2008, at 7:00 PM in the Access Grid Room at WPI in Worcester, MA USA. Currently, we don't have a speaker for the meeting, but if anybody wishes to volunteer, please send me email. I'd be curious to see a demo of (K)Ubuntu Hardy 8.04 if anybody has one available. See ya there! Andy - -- Andy Stewart, Founder Worcester Linux Users' Group (http://www.wlug.org) Chelmsford Linux Meetup Group (http://linux.meetup.com/393) Amateur Radio: KB1OIQ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFIzvzSHl0iXDssISsRAqL0AJ0cF3oe5XDFH43fL5MAfApRVTzrHgCfQmRF +rJjaZcg8at52lND2aPVENY= =EKXD -----END PGP SIGNATURE-----

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Fwd: REMINDER: Upcoming Meeting on Wednesday
by James Gray Sept. 16, 2008

Sept. 16, 2008

Did you mean 8.04 or 8.10? There are already alphas available for 8.10. I would kind of like to see a demo of the features in this next release. ---------- Forwarded message ---------- From: Andy Stewart <andystewart(a)comcast.net> Date: Mon, Sep 15, 2008 at 8:24 PM Subject: [Wlug] REMINDER: Upcoming Meeting on Wednesday To: Worcester Linux Users Group <wlug(a)mail.wlug.org> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 HI gang, The next WLUG meeting will be on Wednesday, September 17th, 2008, at 7:00 PM in the Access Grid Room at WPI in Worcester, MA USA. Currently, we don't have a speaker for the meeting, but if anybody wishes to volunteer, please send me email. I'd be curious to see a demo of (K)Ubuntu Hardy 8.04 if anybody has one available. See ya there! Andy - -- Andy Stewart, Founder Worcester Linux Users' Group (http://www.wlug.org) Chelmsford Linux Meetup Group (http://linux.meetup.com/393) Amateur Radio: KB1OIQ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFIzvzSHl0iXDssISsRAqL0AJ0cF3oe5XDFH43fL5MAfApRVTzrHgCfQmRF +rJjaZcg8at52lND2aPVENY= =EKXD -----END PGP SIGNATURE----- _______________________________________________ Wlug mailing list Wlug(a)mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug

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(redhat,fedora)(LONG) yum.repos.d? for local-net base RPMs
by Doug Mildram Sept. 8, 2008

Sept. 8, 2008

Hi! I had imperfect luck googling the best/easiest answer to this one. Maybe I just need a good "yum book/tutorial". I may have solved (poorly or OK) my "simulated challenge" (planning for an RHCE exam) which is: Let's say I had no Internet, but I did have RedHat RPM's on a local server, so doing a new-install with JUST the first boot cd, then linux askmethod (chose ftp/nfs/http, whatever the server's offering) And did the install using network'd RPMs. Later, say I wanna "yum install" something-else missed earlier, without manually pointing to RPMs. (keep using yum, without Internet). Out of the box, yum didnt adjust itself to my "askmethod" location. Tis on the RHCE exam prep list: "configure to update/install pkgs from remote repositories using yum or pup" I'll attempt (poorly,toomuch...) to finetune a more specific QUESTION: .....................How to modify the yum (config or yum.repos.d/files) IN ORDER TO: either REPLACE ( I managed this) or ADD TO (more intelligently) to use a local-network source for "base RPMs" (whatever comes on the .iso CD/DVD's , a likely RPM stash/set) Here's one answer that might be OK in the isolated situation: a) Comment OUT primary line in /etc/yum.repos.d/*file within [base] (ymmv, "baseurl" or "mirrorlist" line, look for comments/fallbacks) then b) add ONE LINE "baseurl=ftp:...", whatever the server's offering. I'll assume ==dumb to create a NEW /etc/yum.repos.d file with [base] or [??] Also assume there's better ways to solve this. ====== here's a comparison of a centOS 4 vs rhel 5 /etc/yum/repos.d : CentOS release 4.5 (Final) [doug]$ pwd /etc/yum.repos.d [doug]$ grep \\\[ * CentOS-Base.repo:[base] CentOS-Base.repo:[update] CentOS-Base.repo:[addons] CentOS-Base.repo:[extras] CentOS-Base.repo:[centosplus] CentOS-Base.repo:[contrib] CentOS-Media.repo:[c4-media] ==== centOS 5 looks the same as above/centOS4. but RHEL 5 is quite different in yum.repos.d below:=======RHEL 5 workstation: $ cat /etc/redhat-release Red Hat Enterprise Linux Client release 5.2 (Tikanga) [doug]$ ls /etc/yum.repos.d rhel-debuginfo.repo # ONLY ONE short FILE , # and it's ignored ("enabled=0") anyways. ## NOTE LACK OF visible [base], [updates], etc.... So there's some hidden magic here, neither in /etc/yum.conf. [doug]$ cat /etc/yum.repos.d/rhel-debuginfo.repo [rhel-debuginfo] name=Red Hat Enterprise Linux $releasever - $basearch - Debug baseurl=ftp://ftp.redhat.com/pub/redhat/linux/enterprise/$releasever/en/os/… enabled=0 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release oops, too much info. Favorite yum pointer for this topic, or just advice welcome! thx -doug

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OPENINGS in MA - Multiple Linux kernel roles contract & perm (mid to Prin level)
by John Spencer Sept. 3, 2008

Sept. 3, 2008

We have several clients in MA with openings for Linux engineers. I have included some info below, but have not included all roles. If you are interested in hearing/finding out more details, please give me a call at the # below or send me an email with your updated resume. We also have a referral bonus program so if you know someone else looking, please forward this along to them. Linux drivers/kernel builds (12+ mth contract in northern MA) KEYS: Scope of Responsibilities/Expectations; Mid/Senior level software developer responsible for user mode device drivers and Linux kernel builds, configurations and customizations. Additional responsibilities include upgrade, download, install of Linux and application software on a running Linux system with little disruption of normal operation. - Candidate should have experience in Linux tool chain, runtime library and utility configuration, and building. Detailed understanding of the interaction of these utilities and the underlying Linux environment is required. Linux Kernel Engineer (perm in 495/Mass Pike area) Responsibilities: A minimum of 8 years of software development experience with a focus on operating systems, and device drivers, preferably on Linux or a UNIX variant. Proficient in Linux Kernel Architecture, the Linux 2.4 and 2.6 Kernels, Experience working with complex state machines. Experience developing Linux kernel mode and user mode device drivers. Linux Engineer (perm in northern MA) Our customer is looking for a Software Engineer with C/C++ (strong C preferred) and Linux based user space application software development experience (not embedded). Must have Excellent C programming and debugging skills, should have some C++ as well. Excellent design and specification skills Strong written and verbal communication skills Experience with networking and distributed systems Understanding and experience designing and implementing socket, multithreaded and multi-process application Linux and Embedded system experience. Regards, Optimal Engineering Partners Inc. is now Symphony Services! John Spencer Office: 978-256-1113 ext 7608 Fax: 978-256-1184 jspencer(a)symphonysv.com <mailto:risaac@symphonysv.com> Symphony Services 1 Technology Park Drive Westford , MA 01886 www.symphonysv.com <blocked::file:///C:\Documents%20and%20Settings\hripley-boyd\Application %20Data\Microsoft\Signatures\www.symphonysv.com> This electronic transmission (and any attached documents) contains information from Symphony Services and is for the sole use of the individual or entity it is addressed to. If you receive this message in error, please notify me and destroy the attached message (and all attached documents) immediately.

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CNR updating?
by Bill Mills-Curran Sept. 2, 2008

Sept. 2, 2008

I put linspire on a laptop many months ago (better support for my wireless card). I would have expected some kind of notification that software updates are available for applications, but I see nothing indicating that I should update things. I'm using ubuntu on other systems, so I'm familiar with that update method. What do I do to poll for updates with CNR? Thanks, Bill

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raid1
by Simeon MacMillen Aug. 27, 2008

Aug. 27, 2008

I'd like to set up Raid-1 on my computer. I have 2 500Gig hds, one of which is empty, and one of which has data (that I want to keep). I found this guide, https://wiki.ubuntu.com/Raid (I use Ubuntu), and liked the "super simple md" recipe, but I'm not sure how to do this so that I don't loose data. (I searched around, but the only thing I found required the alternate install CD, which I have issues with.) Any help would be appreciated. Simeon MacMillen

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clarification, raid
by Simeon MacMillen Aug. 26, 2008

Aug. 26, 2008

On Tue, Aug 26, 2008 at 12:43 PM, Doug Mildram <dmildram(a)gmail.com> wrote: > for safety how bout a 3rd disk > OR box on your network to ftp/push a "dump" or "tar" file to? Are you suggesting that I don't use Raid at all or that I just back up my stuff before I start? > > stated otherwise, how much data to copy (vs what size older disks do > you have in the near-junk-pile?) I have more data on the 500 Gb drive than I have space on my spare 80 Gb drive...so it sounds like backing up is not an option (unless you have another idea). I might add that the drives have about 7 partitions each. Would it be possible to set up raid one partition at a time, backing up each partition b/f setup? Simeon > (I know: the fun answer is the one that's the coolest. Who doesnt > cross their fingers doing a "resize2fs"?) > > I'm home studying UNIX/rh/lvm/etc anyways so if you wanna call, I'd > probably enjoy helping/talking. > > -doug 508 847 8926 >

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OPENING - Linux kernel build role (mid to Sr level)
by John Spencer Aug. 26, 2008

Aug. 26, 2008

Our client in MA has an opening for a Mid to Sr level Linux kernel engineer. This is a 12+ mth contract. Linux Kernel Build Engineer Scope of Responsibilities/Expectations; Mid/Senior level software developer responsible for some user mode device drivers but mostly Linux kernel builds, configurations, and customizations. Candidate is expected to have some experience of design and implementation of Linux device-drivers and or system utilities and have worked in a fast paced environment Specifics: - 5+ years experience with C, C++ or assembly-language programming for Linux. * 2+ years experience designing, developing and implementing Linux and/or Unix device drivers. - Willing to do debug and code optimization, boot sequencing, linking, initial down loader, and performance tuning type work - The candidate must be adaptable, flexible and willing to take on new challenges. - The candidate must be a team player, and must be able to work with multiple engineering and cross-functional teams. Additional Desirable Skills - Working with Broadcom and MIPS based processors/targets * Experienced with hardware features such as CPU/memory architectures, DMA engines, Boot loaders, I2C, PCI, Ethernet, USB, IEEE-1394, RS-232, etc. Regards, Optimal Engineering Partners Inc. is now Symphony Services! John Spencer Office: 978-256-1113 ext 7608 Fax: 978-256-1184 jspencer(a)symphonysv.com <mailto:risaac@symphonysv.com> Symphony Services 1 Technology Park Drive Westford , MA 01886 www.symphonysv.com <blocked::file:///C:\Documents%20and%20Settings\hripley-boyd\Application %20Data\Microsoft\Signatures\www.symphonysv.com> This electronic transmission (and any attached documents) contains information from Symphony Services and is for the sole use of the individual or entity it is addressed to. If you receive this message in error, please notify me and destroy the attached message (and all attached documents) immediately.

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I'm running late this evening.....
by Andy Stewart Aug. 21, 2008

Aug. 21, 2008

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ...so if I'm not there right at 7:00 PM, please start without me. I should be there by 7:10 PM at the latest, traffic permitting. Thanks, and my apologies, Andy - -- Andy Stewart, Founder Worcester Linux Users' Group (http://www.wlug.org) Chelmsford Linux Meetup Group (http://linux.meetup.com/393) Amateur Radio: KB1OIQ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFIreoMHl0iXDssISsRApv8AJ4w2BZvh//ODIBZGtwyq1B+mSsD+ACcD6DX lp0vCxqmXKNTryin+zFly2I= =q8DI -----END PGP SIGNATURE-----

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