Hi Boaz, Boaz Harrosh wrote: > On 08/31/2010 01:17 AM, Sakari Ailus wrote: >> Hello all, >> >> I'm a long-time UML user and lately I've become a bit worried on the >> state of the UML. This list, as well as the -user one, is very quiet >> these days. Is there someone still actively developing the UML? I have >> to say I really like it! Running Linux on Linux reliably and >> efficiently, just what I need! :-) >> >> I'm currently running three UML virtual machines on an server using >> Athlon XP-M. The host is running 2.6.31 and the guests are 2.6.27. >> >> I cannot upgrade neither host nor guests due to these problems: >> >> - SKAS 3 patches available up to 2.6.31 only. Merging this to current >> kernel might not be a problem, just some work, but: >> >> - Severe data corruption on guest on recent guest kernel versions. I'm >> using a few hard disk partitions directly for UML guests. Something >> after 2.6.27 guest breaks this quite badly. Even for small data sets >> like 100 MiB, copying a file to a different location on guest and then >> running md5sum on both often produces a different result. >> >> Do I have any options than to switch to Qemu and suffer the performance >> penalty from emulation (kqemu is obsolete, too) or to switch to newer >> hardware that supports kvm? Qemu performance is somewhat less than 10 % >> of the native (or UML) performance. >> >> I also found something called lguest but haven't given it a try yet. >> Looks the most interesting but that doesn't seem to have much list >> activity either. So it works perfectly for almost everyone or has few >> users... ;) >> >> How are others coping in the current situation? Or is it just me who has >> these troubles...? >> > > I hear you ... > > I'm using UML for years, as my developing platform for new Kernel code. > You can imagine how it shortens the development cycle. For guests I must > use the absolute newest Kernel all the time. So ... > > - Please send a detailed bug report about that data corruption so someone > can reproduce it. I'm not sure what block device you are using but it has > a bug. If you have a good version 2.6.27 and a bad version 2.6.28. It > should > be easy to "git bisect" to the exact patch that broke the system, and > should > be easy to fix. (Tell me if you need help, it's easy really)
I did write about this back then but it seems no-one else had the same problem. It's one thing to find it and the other to fix it. My wild guess is that it's not a change to that actual driver that broke it. > - I probably don't have your problem because in my UMLs /home is an NFS > mount to the office /home server. And any other data intensive work > is done over iscsi mounts. Look into iscsi Qemu mangament tools , they > should work well for UML as well. (Note you'll need to kconfig scsi and > iscsi in your guest compile, they are off by default) > (The general rule is any UML specific drivers tend to rot faster then > any generic driver like iscsi or nfs) Using NFS root would indeed be another option. > - SKAS 3: haaa SKAS3, that one is abandoned. It will need a maintainer to > get it alive again. How much better is it? do you have some numbers. > (I never used it, the all point was to keep the desktop (host) with a > distro Kernel, nvidia and all that) SKAS4 was supposed to replace it and I think I even used it for a while but the current SKAS4 patch is even older than SKAS3. SKAS 4, as far as I understand, would be a long-term solution since the /dev/mm approach of SKAS 3 wasn't accepted by Linus. <URL:http://user-mode-linux.sourceforge.net/old/skas.html> You do need that to get decent performance with UML and at some point some years ago perhaps, I couldn't get it even working without. Regards, -- Sakari Ailus sakari.ai...@iki.fi ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
