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KVM vs Xen
by Russell Coker 04 Nov '15

04 Nov '15

Xen has been widely regarded as the best performance VM for Linux for a long time. Oracle has been one of the advocates of Xen claiming very close to native hardware performance. # 300% improvement in UnixBench score, with a KVM Linode vs a Xen Linode # 28% faster at compiling a Linux kernel with a KVM Linode vs a Xen Linode # Boot and shutdown times are greatly improved Now Linode (one of the largest Xen sites) is moving to KVM, they list the above as benefits of KVM which surprises me. My experience of Xen is that the only way anything could be 300% faster is if it's an issue of disk IO scheduling on hard drives (as multiple virtual machines on the same spinning media causes contention and/or fragmentation issues depending on how you do it. But given that Linode was already using SSD for all storage that's obviously not what they are doing. The last time I tried KVM on my laptop the performance was a lot slower than native performance as opposed to Xen which was near enough to native hardware performance that the difference didn't matter. I've never even tested KVM on a server because the performance on my laptop (admittedly a couple of years ago) was very disappointing. Last time I tested KVM performance was not only noticably worse (EG compiles of selinux-policy-default taking about 50% longer) but the increase in CPU use was an issue of cooling. Has KVM improved a lot recently? How can anything be so much better than Xen when Xen has been so close to native performance for so long? I've just chosen KVM for a new Linode instance. They allow me to choose Xen but say that KVM is the way of the future - presumably I would be forced to use KVM sooner or later so it seemed easier to use it now. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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Help fixing grub install
by Toby Corkindale 04 Nov '15

04 Nov '15

Hi, After re-installing Kubuntu on my (EFI, GPT) laptop (which also has Windows 10), I've ended up with a broken grub. It used to work fine. The problem is that now it boots into grub, with no configuration, just the grub> prompt. I can continue by typing: grub> configfile (hd0,gpt6)/boot/grub/grub.cfg which then brings up the usual menu. But I'd like to know how to configure grub so that it finds it automatically! Needless to say, I have already tried running grub-install /dev/sda after booting. (Which succeeds without error) Any suggestions? PS. I don't want to totally blank the drive, as it shares with a Windows 10 install that I'd like to keep. Thanks Toby

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Cheap Android phones
by Russell Coker 04 Nov '15

04 Nov '15

https://www.kogan.com/au/buy/kogan-agora-3g-lite/ $99 for a Kogan phone running Android 5. As you would guess from the price it's got low hardware specs, less than a Samsung Galaxy S3. But it should do the basics. A friend has been using the cheapest Kogan phones for a while and found that the build quality is a bit lacking. They can't be expected to work as well as an old S3. But if you want a new phone for $99 I think it's a good deal! -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/

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SSHFS - suddenly no write
by Piers Rowan 29 Oct '15

29 Oct '15

Hi there, I have been using sshfs for years on a server without incident. Now when I connect I can't write to / save the PHP files I am editing. The server shows the following error: sftp-server[34002]: error: process_write: write failed I have checked the disk for space (there is plenty and I have even deleted files). The permissions have not changed and I have tested and reset them on various directories. Geany: Error saving file. Nautilus: Error creating directory: Operation not permitted Any ideas how to debug? I think it is specific to this server. Thanks Piers

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Simple outgoing mail setup
by zlinw＠mcmedia.com.au 27 Oct '15

27 Oct '15

I run a small network of 4 machines, it is not really a network, this connection being basicly a handy way of getting data between machines. Because of this there is no name server or mail server running on any machines For out going mail I have always ssh'ed to the machine with the internet connection and used pine, which has inbuilt support for outgoing mail. Unfortuantely this no longer works as I now do not have direct access to my ISP's mail server and access via the internet requires authentication and pine does not support that. How is outgoing mail set up done on a standard desktop system, a text based email client on the internet access machine is the only one that will be used. Hopefull something simple. Although I have been running linux now for well over twenty years, network connections between my machines has always just worked and I have always used pine, as a consequency I have learned little of this side of Linux configuration. Kernel and X server config are different stories though Lindsay

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remote screen sharing
by Michael Schams 26 Oct '15

26 Oct '15

Hi there, I wonder which cross-platform software or services you are using for remote screen sharing sessions, if any? Commercial vendors with proprietary software make it (more or less) easy for Windows and Mac users to share their screens remotely, fool-proof even for non-tech-savvies (e.g. Skype, WebEx, GoToMeeting, zoom.us or browser-based such as Google Hangouts, etc.). A typical situation would be: I use Debian 8 and I want to share my screen with a client or partner running Windows or Mac to demonstrate something. My experience so far: Skype works well under Debian, but I always have issues with the screen sharing feature. I have used TeamViewer from time to time (works very well). WebEx, GoToMeeting, zoom.us and most of the other services don't support Linux. Remote Desktop (RDP) predominantly aims to remote administration. Browser-based solutions I have not tested yet. I would prefer open source solutions of course (even paid). Must haves: very easy to use for the "other side" and cross-platform capability (Linux, Windows, Mac). Optional: audio (voice) support would be nice but could also be achieved via VoIP/Skype/phone via an extra channel. One-to-many (someone shares his/her screen to multiple receivers) would be also nice, but an exception. Does anyone have any experience, suggestions, advices in this regards? Thanks Michael

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No need for YACS in Mint?
by Carl Turney 26 Oct '15

26 Oct '15

Hi All, Many years ago, I needed to install YACS (yet another clock synchronizer) into my Red Hat (?) system, to keep my hardware clock from "drifting" over time. No mention of it, or anything on clock synchronizers, that I can find for my Linux Mint 17 Qiana. Not needed? Handled elsewhere as a standard feature? Thanks, Carl Turney Bayswater, Vic

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Re: Problem with a new 3G moble broadband set up
by zlinw＠mcmedia.com.au 26 Oct '15

26 Oct '15

On Sun, 25 Oct 2015 14:02:12 Craig Sanders said, > do you know someone who has a mobile phone that will let you borrow it > for 10 minutes? > perhaps they have an old phone buried at the bottom of a drawer? > craig On thinking the current situation over I do not regard it as serious enough to bother any one with something I know so little about (I have never had or used a current mobile phone). As mentioned I currently have broadband access to Virgin with the modem, a Huawei E220, Now I do have a Huawei E160 (Note 1) as a spare. I have currently put it away and cannot find it, but but will surface soon as I am cleaning up my computor room today. Another option probably worth pursuing is an external router that can use a 3/4G modem such as the Netcom Wireless 4GM3W with a Netcom N600, the latter does not have linux suppport but the I assume the 4GM3W does. Further research is required. Of course a real good solution is to find a couple of Belkin micro N300's (one as a spare) Belkin Australia claim these are readily availible. Note 1: The Huawei E160 is a slightly cut down version of the E220. Note 2: I did a lot of web searching and ringing around yesterday and was offered 3 different mobile broadband dongles, none of which had in built linux kernel support, _______________VERY_______________ frustrating I may say. Lindsay

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Re: Problem with a new 3G moble broadband set up
by zlinw＠mcmedia.com.au 25 Oct '15

25 Oct '15

On Fri, 23 Oct 2015 17:52:30 Piers Rowan said, > Have you tested it in a typical device - phone/tablet? No, I do not have anything (I can find) to test it on, I do have another USB 3G modem I cannot at the moment find it. I do not (and never will have) a mobile phone. On Fri, 23 Oct 2015 21:06:31 Keith Bainbridge said, > I used this for a couple of years on my laptop: I am almost 100 percent sure its not a configuration issue. I have checked my config with three on line sources, one of which was specfic to Optus (both Virgin and Bendigo Telco use Optus) and everything checks out ____including___ the APN. Looking at the data comming back it looks like the connection reachs the Bendigo Telco servers and these are sending back a SIGHUP (a hangup signal). My current theory is the optus network must be sending an incorrect id to the Bendigo servers, which means a faulty sim. The problem is of course they do not support Linux and are blaming that, and I cannot try it on windows as the dongle is no longer switched to the mode windows requires it in (Note 1). For various reasons including I am not sure how to do it, I do not want to switch it back. Note 1: When one get it it looks like a USB hardisk, Windows copies the installation software from the dongle. when this is exicuted it switch's the dongle into operational mode. In this it has 3 serial ports a hardisk and a ram disk. > On another issue, is the modem locked? No Lindsay

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IRC training
by Russell Coker 24 Oct '15

24 Oct '15

Who is interested in IRC based training? The idea would be to setup a bunch of virtual servers and then have people login to them, work through a training course, and ask questions on IRC. If we did that for the more technically demanding hands on training sessions then the Beginners' SIG can be kept free for beginners. Also for things that require significant server resources (like the BTRFS and ZFS session) we could spread it out over an entire day to keep the server load down. -- Sent from my Samsung Galaxy Note 3 with K-9 Mail.

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