X-Git-Url: http://git.annexia.org/?p=virt-mem.git;a=blobdiff_plain;f=virt-mem.pod;fp=virt-mem.pod;h=1c81e29831b5bff9dde8c3d570aa4d384f8d2323;hp=f5dc3c34443d03230718ec234e47a6b31c30a518;hb=e4a9a58795f30b85fd965e6584ca73d7b0a812f8;hpb=9414deeb6210c5f2c5219c6e99eb329b4bb1be26 diff --git a/virt-mem.pod b/virt-mem.pod index f5dc3c3..1c81e29 100644 --- a/virt-mem.pod +++ b/virt-mem.pod @@ -1,28 +1,27 @@ =head1 NAME -virt-df - 'df'-like utility for virtualization stats +virt-uname - system information for virtual machines + +virt-dmesg - print kernel messages for virtual machines =head1 SUMMARY -virt-df [-options] +virt-uname [-options] [domains...] + +virt-dmesg [-options] [domains...] =head1 DESCRIPTION -virt-df is a L-like utility for showing the actual disk usage -of guests. Many command line options are the same as for ordinary -I. +These virtualization tools allow you to inspect the status of +virtual machines running Linux. -It uses libvirt so it is capable of showing stats across a variety of -different virtualization systems. +The tools all use libvirt so are capable of showing stats across a +variety of different virtualization systems. -=head1 OPTIONS +=head1 COMMON OPTIONS =over 4 -=item B<-a>, B<--all> - -Show all domains. The default is show only running (active) domains. - =item B<-c uri>, B<--connect uri> Connect to libvirt URI. The default is to connect to the default @@ -33,84 +32,109 @@ libvirt URI, normally Xen. Print the results in CSV format, suitable for importing into a spreadsheet or database. -This option is only supported if virt-df was built with CSV support. +This option is only supported if virt-mem was built with CSV support. =item B<--debug> Emit debugging information on stderr. Please supply this if you report a bug. -=item B<-h>, B<--human-readable> - -Display human-readable sizes (eg. "10GiB" instead of large numbers). - -=item B<-i>, B<--inodes> - -Display inode information. - -This option only works for Unix-like filesystems. - =item B<--help> Display usage summary. -=item B<-t diskimage> +=item B<-t memoryimage> Test mode. Instead of checking libvirt for domain information, this -runs virt-df directly on the disk image (or device) supplied. You may +runs the virt-mem tool directly on the memory image supplied. You may specify the B<-t> option multiple times. =item B<--version> Display version and exit. +=item B<-E auto|littleendian|bigendian> + +=item B<-T auto|i386|x86-64|I
> + +=item B<-W auto|32|64> + +These options force the endianness, text address, and word size for +the subsequent domains listed on the command line (or if no domains +are listed, then for all domains). + +These default to I which tries to do automatic detection (using +libvirt, or details from the memory images themselves). You only need +to use these options if virt-mem tools get the automatic detection +wrong. + +Endianness (I<-E>) sets the memory endianness, for data, pointers and +so on. + +Text address (I<-T>) sets the base address of the kernel image. I<-T +i386> means to try some common addresses for i386-based kernels. I<-T +x86-64> means to try some common addresses for x86-64-based kernels. +I<-T I
> sets the address specifically (I<0x> prefix is +allowed to specify hex addresses). + +Word size (I<-W>) sets the word size, 32 or 64 bits. + +=item B<-A auto|i386|x86-64|...> + +This option sets the architecture to one of a collection of known +architectures. It is equivalent to setting endianness and wordsize in +one go, but not text address. + =back -=head1 EXAMPLE +=head1 EXAMPLES + + # virt-uname + f9x32kvm: Linux localhost.localdomain 2.6.24-0.155.rc7.git6.fc9 #1 + SMP Tue Jan 15 17:52:31 EST 2008 i686 (none) - # virt-df - Filesystem 1K-blocks Used Available Type - f9x32kvm:hda1 190740 24817 165923 Linux ext2/3 - f9x32kvm:VolGroup/LogVol00 6568348 3401656 3166692 Linux ext2/3 - f9x32kvm:VolGroup/LogVol01 1015808 Linux swap + # virt-dmesg f9x32kvm | tail + <6>Bluetooth: Core ver 2.11 + <6>NET: Registered protocol family 31 + <6>Bluetooth: HCI device and connection manager initialized + <6>Bluetooth: HCI socket layer initialized + <6>Bluetooth: L2CAP ver 2.9 + <6>Bluetooth: L2CAP socket layer initialized + <6>Bluetooth: RFCOMM socket layer initialized + <6>Bluetooth: RFCOMM TTY layer initialized + <6>Bluetooth: RFCOMM ver 1.8 + <7>eth0: no IPv6 routers present =head1 SHORTCOMINGS -virt-df spies on the guest's disk image to try to work out how much -disk space it is actually using. There are some shortcomings to this, -described here. - -(1) It only understands a limited set of partition types. Assuming -that the files and partitions that we get back from libvirt / Xen -correspond to block devices in the guests, we can go some way towards -manually parsing those partitions to find out what they contain. We -can read the MBR, LVM, superblocks and so on. However that's a lot of -parsing work, and currently there is no library which understands a -wide range of partition schemes and filesystem types (not even -libparted which doesn't support LVM yet). The Linux kernel does -support that, but there's not really any good way to access that work. - -The current implementation uses a hand-coded parser which understands -some formats (MBR, LVM2, ext2/3, DOS FAT, Windows NTFS, Linux swap and -Linux suspend partitions). - -(2) The statistics you get are delayed. The real state of, for -example, an ext2 filesystem is only stored in the memory of the -guest's kernel. The ext2 superblock contains some meta-information -about blocks used and free, but this superblock is not up to date. In -fact the guest kernel may not update it even on a 'sync', not until -the filesystem is unmounted. Some operations do appear to write the -superblock, for example L [that is my reading of the ext2/3 -source code at least]. +The virt-mem tools spy on the guest's memory image. There are some +shortcomings to this, described here. + +(1) Only works on specific, tested releases of Linux kernels. Support +for arbitrary Linux kernel versions may be patchy because of changes +in the internal structures used. Support for non-Linux kernels is +currently non-existent, and probably impossible for Windows because of +lack of an acceptable source license. + +(2) Heuristics are used which may mean in the worst case that the +output is wrong. + +(3) Structures which are frequently modified may cause errors. This +could be a problem if, for example, the process table in the guest is +being rapidly updated. + +(4) We have to scan memory to find kernel symbols, etc., which can be +quite slow. Optimizing the memory scanner would help, and caching the +base address of the symbol table(s) would make it dramatically faster. =head1 SECURITY The current code tries hard to be secure against malicious guests, for -example guests which set up malicious disk partitions. +example guests which set up malicious kernel memory. =head1 SEE ALSO -L, +L,L, L, L, L, @@ -124,7 +148,7 @@ Richard W.M. Jones =head1 COPYRIGHT -(C) Copyright 2007-2008 Red Hat Inc., Richard W.M. Jones +(C) Copyright 2008 Red Hat Inc., Richard W.M. Jones http://libvirt.org/ This program is free software; you can redistribute it and/or modify @@ -146,7 +170,7 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. Bugs can be viewed on the Red Hat Bugzilla page: L. -If you find a bug in virt-df, please follow these steps to report it: +If you find a bug in virt-mem, please follow these steps to report it: =over 4 @@ -160,16 +184,16 @@ have fixed it. Run - virt-df --debug > virt-df.log 2>&1 + virt-[program] --debug > virt-mem.log 2>&1 -and keep I. It contains error messages which you should +and keep I. It contains error messages which you should submit with your bug report. -=item 3. Get version of virt-df and version of libvirt. +=item 3. Get version of virt-mem and version of libvirt. Run - virt-df --version + virt-[program] --version =item 4. Submit a bug report.