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systemd-logind memory limit
by Russell Coker 22 May '17

22 May '17

The traditional way of limiting memory use by users is to set a per-process limit of memory use "as" in /etc/security/limits.conf and also limit the number of processes. Therefore the amount of memory that may be used is the address space limit multiplied by the number of processes. This isn't that good. For example if a user is compiling C++ software the g++ program can take quite a lot of RAM and there will also often be plenty of shell scripts etc running. The RAM requirements for a g++ process multiplied by the number of processes reasonably needed for a couple of login sessions and all the scripts for building may be more than you want to allocate to them. As an aside I'm thinking of how I killed some Unix servers while doing assignments for Unix Systems programming when I was in university. :-# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=860410 An additional problem is that there's a bug in recent versions of sshd in that limits.conf applies to the sshd process. https://manpages.debian.org/testing/systemd/logind.conf.5.en.html When you use systemd the systemd-logind creates a new cgroup named user-$UID.slice. # cat \ /sys/fs/cgroup/memory/user.slice/user-506.slice/memory.max_usage_in_bytes 99999744 http://tinyurl.com/mhjb8ct I've set the max_usage_in_bytes to 100M (see the above Red Hat URL for an explanation of this). But it doesn't seem to work, I've written a test program that allocates memory and sets it via memset() and it gets to the ulimit setting without being stopped by the cgroup limit. Any suggestion on how to get this going properly? The next problem of course will be having systemd-logind set the limit when it creates the cgroup. Any suggestions on that will be appreciated. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Resizing jpegs, limiting file size
by Mark Trickett 22 May '17

22 May '17

Hello All, I am wanting to cut the file size of photos from my phone. I have tried opening in GIMP, but takes a bit of mousing and clicking around, and even saving/exporting several times to get the size down. I think the imagemagik suite should be able to do, but my reading of the man pages does not make it apparent to me. They talk of resizing, but it looks like the linear extent, rather than loosing some detail of the same extent of image. I would appreciate any contributions. regards, Mark Trickett

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Resizing jpegs, limiting file size
by Andrew Greig 19 May '17

19 May '17

Hi Mark, Early in the thread I suggested using Darktable to resize your jpgs from your Nokia. And at that stage your reply was that you thought it would not resize them as your input files were also jpg. Well I found the time to try it out tonight when I had to resize a rather large proof for uploading, and it does a fantastic job of resizing a jpg. And with its ability to handle batch processing you could knock the whole lot over quite quickly. I found that the the "quality" setting for the jpg was the greatest controller of file size and in the end I settled on 2000 x 1500 px at 95% quality for 660 Kb wheras at 90% the size was a bit over 200Kb, there is also a switch to prevent up-scaling. So, if you loaded all your shots into Darktable, nominated your folder for export, set the size and quality, hit Ctrl+ A, and then the export button, in no time flat (depending on RAM and CPU) you will have your result. Cheers Andrew Greig

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Fwd: possible grant request for training server
by Russell Coker 15 May '17

15 May '17

I want to run more hands-on training sessions with virtual machines and I want to do some of them remotely to train people in other parts of Australia. The servers we currently have are inadequate because we have nowhere to run them 24*7. So here is the message I sent to the Linux Australia list. ---------- Forwarded Message ---------- Subject: possible grant request for training server Date: Sun, 14 May 2017, 02:39:59 PM From: Russell Coker <russell(a)coker.com.au> To: "linux-aus(a)linux.org.au" <linux-aus(a)linux.org.au> NB This is not an actual grant request. This is a discussion prior to determining what grant to request. It could be that LA members offer what is needed without the need for an LA grant request. http://tinyurl.com/pkqpgyx The German hosting company Hetzner offers a range of very affordable servers at low prices, the above URL has links for some of their best value for money offerings which includes E39 ($57.70 according to xe.com) per month for a system with 64G of RAM and 2TB of RAID-1 storage (250G of SSD isn't enough and 500G of SSD makes it too expensive). For some years my blog has been hosted on a VM on such a Hetzner server and the LUV server is on another VM on the same system. So Hetzner has been working well. In the past LUV has run a number of training sessions about system administration. This has included setting up DNS, mail servers, Cassandra, BTRFS, and ZFS. Those sessions have been well received. I am sure that other LUGs in Australia could run similar hands on training sessions. I don't think that the grant required would be justified for just LUV use, but I anticipate that other LUGs in Australia will make use of it - if only to go through the course work that I and others have prepared for LUV. But I really hope that other LUGs will develop course work too. If we had a spare server for running VMs, I would be happy to run the Dom0 and set things up to allow people from various LUGs to grant access to VMs to their members for training sessions at meetings and also for online training over IRC or other IM systems. Another possibility instead of Hetzner is that I have an offer of free hosting in Melbourne with a reasonable number of IPv4 addresses (maybe dozens of addresses as opposed to Hetzner offering few addresses and making you pay extra for them). But that free hosting requires a system that's not too noisey (I was told to remove a previous system LUV had for this purpose because of the noise). If someone has a spare system with 32G+ of RAM and isn't noisey (IE not rack mount) then that would be an option. http://www.dell.com/au/business/p/poweredge-t30/pd A Dell PowerEdge T30 can take up to 64G of RAM and starts at $1,087 (maybe less with RACV discount). I'm not sure how much it costs to expand it to 64G, the Dell web site isn't helpful in this regard. I am not set on Dell, it's just a really easy way of getting a price to start the discussion. As an aside buying a Dell will be cheaper than renting at Hetzner for 2 years. If an LA member has a tower server that's they don't need which can take a suitable amount of RAM then that would be great, CPU power is not a requirement, just RAM and storage. If such a server isn't in Victoria then I'll apply for an LA grant for courier fees. Please offer any suggestions about cheaper ways of achieving these goals. If you want to start a more general discussion about servers for running Linux then please change the subject. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ ----------------------------------------- -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Dell Server, ESX 6.5 and iSCSI
by Peter Ross 15 May '17

15 May '17

Hi all, we have new Dell Servers with Dell's VMware ESX 6.5 installed. They have multiple 10GB interfaces. With NFS we get expected speed, basically to flood the disks up to their limits. However, with iSCSI the network becomes the bottleneck, we only reach 20% of the possible performance. We installed Ubuntu 16.04 on one of the servers, for testing. With Ubuntu we are able to run iSCSI properly. We tried iSCSI with ESX against a Powerfault MD3860i and against a Synology NAS, both setups show the same slowness. So there must be something wrong with the ESX setup in this environment, I believe. So far we looked at "Best practise guides" for VMWare and tried to play with Jumbo frames, made sure they are enabled (size 9000 as recommended in these guides) on all components and disabled flowcontrol. It did not help. My colleague exhausted all options he can think of, I cannot think of anything either, and we asked VMware but did not have a good answer yet.. Of course it is urgent;-) So I wonder whether I can pick your brains. Do you have any ideas what could cause the issue? Thank you for all ideas Peter

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Installing a non-free deb package into Ubuntu 16.04
by Andrew Greig 09 May '17

09 May '17

Hi, I have been using Corel Aftershot Pro 3 for Linux under OpenSuse and it is fantastic. Recently I bought a new laptop with 12Gb RAM so that I could run post production work away from my desktop, and so I have downloaded the deb package for it, but unlike my experience of RPM, the deb/Ubuntu experience is abysmal. I have tried double clicking on the package in my Downloads folder, but nothing happens. On a Ubuntu forum it was suggested that an upgrade would fix the acknowledged issue, but it hasn't. 17 years of RPM has not equipped me for this. So I would appreciate hearing where I have gone wrong and how I could get it right. Gratefully Andrew Greig

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Re: Installing a non-free deb package into Ubuntu 16.04
by Andrew Greig 09 May '17

09 May '17

There are some things that are worth paying for, and Corel After Shot Pro 3 is one of them. I also use Darktable which is Open Source and excellent. In fact I use Darktable more often these days, but I had about 60 shots of a family event and red eye was common. Careless me, but ASP3 handles red eye reduction in seconds, whereas DT needs work in channels and is not trivial. ASP3 is in constant development, so I frequently need to download and install. But DT is upgraded in the normal cycle of things. I use OpenSuse on my desktop, and the only reason I have Ubuntu on my laptop is because it would install with all the uefi BS, and Open Suse would not. So GIMP and DT and ASP3 and Hugin are all I need for my RAW image processing. I have been a part of the Linux comunity for 17 years now and I am constantly amazed and deeply grateful for the generosity and support that I have received. Thank you all. Andrew On 9 May 2017 9:27 PM, "Andrew Pam via luv-main" <luv-main(a)luv.asn.au> wrote: On 09/05/17 21:04, Erik Christiansen via luv-main wrote: > # apt-get update > # apt-get --install package-name > > where package-name may be elicited by an: > > $ apt-cache search <some-part-of-the-expected-name> | more None of that wll help in this case, where the original request was to install a downloaded commercial third-party package which will certainly not be in the repository. Cheers, Andrew _______________________________________________ luv-main mailing list luv-main(a)luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-main

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Reworking filenames
by Mark Trickett 07 May '17

07 May '17

hello All, I have photos from my mobile phone, an old Nokia 6021, and readily get them onto the PC. The problem is the naming, the first eight characters are the date, two digits for the day, two for the month then four for the year. I wish to reorder them to be year, month and then day. That portion of the filename is then followed by brackets with a three digit sequence number for the second and subsequent photos on the day. it would be good to add the brackets with three zeros when not present. That is followed by a period and the jpg extension. This will let me order by date when viewing in Image Viewer, and a relatively sane sorting of the filenames. There are something over 450 images in the directory that I wish to edit the names of, so better to get the PC to do the repetitive work. My shell programming, and the like, are rusty, what there is of such skills. I would appreciate some assistance and pointers. Regards, Mark Trickett

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Re: Reworking filenames
by Craig Sanders 06 May '17

06 May '17

On Fri, May 05, 2017 at 08:16:52PM +1000, Mark Trickett wrote: > > Most rename scripts you'll write are just one or more > > 's/search/replace/' one-liner statements, but they can be a quite > > complicated perl script if required. > > I need to learn perl, but will do a lot better around other people, most renames won't need much perl, just regular expression search & replace. > > $ rename --version > > /usr/bin/rename using File::Rename version 0.20 > > > > or check 'man rename' - if it mentions perl, it's good. > > That reported perl, but the --version option is not supported on the > rename on this install. that sounds like the default rename included in the perl package. it should work but has some problems that are fixed in later versions. the rename package is only 12 KB in size, so won't use much bandwidth to download. it has no dependencies other than perl, either so I could mail it to you if you want. or download direct from your nearest debian mirror without bothering with 'apt-get' (updating the package lists will be tens of megabytes). install with 'dpkg -i' (as root, of course). Package: rename Version: 0.20-4 Installed-Size: 36 Maintainer: Debian Perl Group <pkg-perl-maintainers(a)lists.alioth.debian.org> Architecture: all Replaces: libfile-rename-perl Provides: libfile-rename-perl Depends: perl Conflicts: libfile-rename-perl Description-en: Perl extension for renaming multiple files This package provides both a perl interface for renaming files (File::Rename) and a command line tool 'rename' which is intended to replace the version currently supplied by the perl package. Description-md5: f25bdadb8b97cbf70a4a78c50ca2e8af Homepage: https://metacpan.org/release/File-Rename Section: perl Priority: optional Filename: pool/main/r/rename/rename_0.20-4_all.deb Size: 12464 MD5sum: 11987300e5cbab887e2b34692665dc3a SHA256: 51ed56802ac8f84b588cc9db117469071e7b434cf8544aab2ef1d66c6686a00f > > but in the meantime, try something like this to start with: > > > > # DD MM YYYY (nnn) > > rename -n 's/(\d\d)(\d\d)(\d{4})\./$3-$2-$1(000)./; > > s/(\d\d)(\d\d)(\d{4})($\d{3}$)\./$3-$2-$1$4./; > > ' *.jpg > > > > the first s/// statement matches and replaces filenames WITHOUT > > the 3-digit sequence (and adds a sequence of "(000)"). The second > > matches filenames WITH them. > > I think I can start to follow what you are doing, and I need to be > careful, In typing emails and the like, I am hitting extra keys the s/// statements above should work with the filenames you listed. and copy-and-paste the rename command into a terminal should also work, no need for error-prone typing. that's part of the reason why I used the '-n' option, so it only does a dry-run and doesn't actually rename anything. or paste it into a text file, insert a first line of '#!/bin/sh', and make it executable with 'chmod +x'. and change *.jpg to "$@" so you can specify the filenames on the command line. like so: #!/bin/bash rename -n 's/(\d\d)(\d\d)(\d{4})\./$3-$2-$1(000)./; s/(\d\d)(\d\d)(\d{4})($\d{3}$)\./$3-$2-$1$4./; ' "$@" get rid of the '-n' when you've tested it and seen that it will work as required. craig -- craig sanders <cas(a)taz.net.au>

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Re: Reworking filenames
by Andrew Pam 05 May '17

05 May '17

On 05/05/17 20:16, Mark Trickett via luv-main wrote: > I was very familiar with the old IBM keyboards, the > ones with a wedge connector and that could have a cable with an AT or > PS/2 connector, but I have yet to find an adaptor from AT/PS/2 to USB > that I can rely on. I have seen a USB mouse with adaptor to PS/2, but > not for a keyboard, yet. They definitely exist; I have both USB keyboard to PS/2 connector and PS/2 keyboard to USB adapters, and have successfully used a AT to PS/2 keyboard adapter stacked with one of the latter. > Having a second keyboard on a laptop would be > "interesting" My Samsung phone supports USB OTG, so in the past I have plugged in a small hub and a mouse and keyboard to use with my phone! The mouse pointer appears as soon as you plug in a mouse. Cheers, Andrew

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