Hi all, refering to the actual mail correspondence, I can give the following update:
on host i have mounted (not by fstab, i think thats automatically done by system) two tmpfs systems (why two systems?) tmpfs 507M 0 507M 0% /lib/init/rw tmpfs 507M 437M 70M 87% /dev/shm it's very interesting, that /dev/shm is filled to 87%. lsof /dev/shm shows, that it is used by uml system. but in uml if i do free, i can see Mem: 512908 (total) 198704 (used) 314204 (free) Actually my question is, why do i have two tmpfs mounts and why is one filled up to 87%, when uml is using only less than 50%? I hope someone can help me with this stuff... Best, Herbert Am Samstag, den 28.04.2007, 14:27 +0200 schrieb Blaisorblade: > On giovedì 26 aprile 2007, Herbert Volkmann wrote: > > Hi Blaisorblade, > > > > thanks for answering that fast: > > Yes, and sorry, but I'm short on time and I do not want private emails - > please reply on the list (on uml-user actually). So anybody else can continue > answering. > > I'll just say to try a more recent kernel first. > > Second suggestion, which is more probably the correct one, where is the UML > RAM file? It goes in /tmp or in /dev/shm usually (lsof, or ls /proc/<host UML > pid>/fd can show what happens - or even df on the host). If the host has 1G > of RAM, by default a tmpfs mount is 512MB wide. If that fills, UML crashes > with a characteristic error message (IIRC 'Kernel mode signal N', where N is > the numeric code of SIGBUS). > > But maybe, since you append con=null, you get no kernel messages at all... > and > that's bad from you. > > > - Filesystem is ext3 on host and uml > > - the things you guessed were right > > - it's a 32bit system > > - uml kernel release 2.6.18, exactly (apt-cache show user-mode-linux): > > Architecture: i386 > > Version: 2.6.18-1um-2 > > > > I do not write to tmpfs, i execute the following command in /root > > dd if=/dev/zero of=test.img bs=1024k count=512 > > right before ending dd, uml crashes, all uml processes end working which > > i can see on host system by executing ps axuf. > > > > what is also interesting is, that i have 256M swap which is never used > > by uml (fstab shows: > > /dev/ubd1 none swap defaults 0 0 > > ) > > > > and i have the same effect when i copy with scp FROM the UML Machine to > > my Host System. cache is increasing, memory goes down and shortly before > > memory is gone, uml stops working. > > > > Any other suggestions from your side? > > > > Thanks for supporting me with this strange behavior, > > Best Herbert > > > > Am Donnerstag, den 26.04.2007, 16:17 +0200 schrieb Blaisorblade: > > > On giovedì 26 aprile 2007, Herbert Volkmann wrote: > > > > Hi List, > > > > > > > > i ran in the following problem: > > > > > > Very strange... > > > > > > > when i produce files (with dd) or copy files to or from the uml > > > > machine, > > > > > > Which filesystems are involved? Can you give a sample command? > > > > > > > i can see (with top), > > > > > > Run on the guest (i.e. UML) I guess, right? > > > > > > > that the used memory and the cached things > > > > increases, while the unused memory will go down. > > > > > > That is reasonable, but the cache should not make the system stop. > > > > > > > shortly before memory > > > > will come to zero, the uml stops working completely without any > > > > messages in the /var/log/* files on uml or host system. > > > > > > > > if i do in between a "echo 3 > /proc/sys/vm/drop_caches" > > > > > > On the guest (i.e. UML) I assume, right? > > > > > > > it cleans caches, frees memory and works fine! but i have to do this > > > > all 10 seconds when i use dd for producing large files ;-( > > > > > > > > these are the components i use: > > > > - debian etch on host with debian kernel patched with skas3 from debian > > > > > > 32bit system, right? > > > > > > > - 1024 MB RAM on host > > > > - RAID5 System with 3ware Controller (5x2G) almost 1 TB > > > > - on uml i use debian etch, with bridged networking, 512MB RAM for uml > > > > > > Which UML kernel release? That's the most important thing. > > > > > > > - 6G root_fs for uml and 256M swap > > > > > > > > here is the command with which i start the uml: > > > > sudo -u uml /usr/bin/linux.uml umid=uml mem=512M eth0=tuntap,tap1 > > > > ubd0=/usr/media/uml-linux/root_fs_2007_04_23 > > > > ubd1=/usr/media/uml-linux/swap_fs con=null root=/dev/ubda uml_dir=/tmp/ > > > > > > > > I would be really happy if someone could tell me what i can test more > > > > to find out why this system is instable with i/o operations and caches. > > > > > > I have only a doubt: if you are filling a shmfs/tmpfs filesystem (which > > > is backed by ram), that's an almost normal behaviour, and can happen even > > > on host systems. > > > > > > > thanx for any reply, > > > > Herbert > > > > -- > Inform me of my mistakes, so I can add them to my list! > Paolo Giarrusso, aka Blaisorblade > http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. 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