" [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
" [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n"
" [,serial=s][,addr=A][,id=name][,aio=threads|native]\n"
- " [,readonly=on|off]\n"
+ " [,readonly=on|off][,copy-on-read=on|off]\n"
+ " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]][[,iops=i]|[[,iops_rd=r][,iops_wr=w]]\n"
" use 'file' as a drive image\n", QEMU_ARCH_ALL)
STEXI
@item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
The default setting is @option{werror=enospc} and @option{rerror=report}.
@item readonly
Open drive @option{file} as read-only. Guest write attempts will fail.
+@item copy-on-read=@var{copy-on-read}
+@var{copy-on-read} is "on" or "off" and enables whether to copy read backing
+file sectors into the image file.
@end table
By default, writethrough caching is used for all block device. This means that
In case you don't care about data integrity over host failures, use
cache=unsafe. This option tells qemu that it never needs to write any data
to the disk but can instead keeps things in cache. If anything goes wrong,
-like your host losing power, the disk storage getting disconnected accidently,
+like your host losing power, the disk storage getting disconnected accidentally,
etc. you're image will most probably be rendered unusable. When using
the @option{-snapshot} option, unsafe caching is always used.
+Copy-on-read avoids accessing the same backing file sectors repeatedly and is
+useful when the backing file is over a slow network. By default copy-on-read
+is off.
+
Instead of @option{-cdrom} you can use:
@example
qemu -drive file=file,index=2,media=cdrom
DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
"-fsdev fsdriver,id=id,path=path,[security_model={mapped|passthrough|none}]\n"
- " [,writeout=immediate]\n",
+ " [,writeout=immediate][,readonly]\n",
QEMU_ARCH_ALL)
STEXI
-@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}]
+@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly]
@findex -fsdev
Define a new file system device. Valid options are:
@table @option
This means that host page cache will be used to read and write data but
write notification will be sent to the guest only when the data has been
reported as written by the storage subsystem.
+@item readonly
+Enables exporting 9p share as a readonly mount for guests. By default
+read-write access is given.
@end table
-fsdev option is used along with -device driver "virtio-9p-pci".
DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
"-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough|none]\n"
- " [,writeout=immediate]\n",
+ " [,writeout=immediate][,readonly]\n",
QEMU_ARCH_ALL)
STEXI
-@item -virtfs @var{fsdriver},path=@var{path},mount_tag=@var{mount_tag},security_model=@var{security_model}[,writeout=@var{writeout}]
+@item -virtfs @var{fsdriver},path=@var{path},mount_tag=@var{mount_tag},security_model=@var{security_model}[,writeout=@var{writeout}][,readonly]
@findex -virtfs
The general form of a Virtual File system pass-through options are:
This means that host page cache will be used to read and write data but
write notification will be sent to the guest only when the data has been
reported as written by the storage subsystem.
+@item readonly
+Enables exporting 9p share as a readonly mount for guests. By default
+read-write access is given.
@end table
ETEXI
+DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
+ "-virtfs_synth Create synthetic file system image\n",
+ QEMU_ARCH_ALL)
+STEXI
+@item -virtfs_synth
+@findex -virtfs_synth
+Create synthetic file system image
+ETEXI
+
DEFHEADING()
DEF("name", HAS_ARG, QEMU_OPTION_name,
iSCSI support is an optional feature of QEMU and only available when
compiled and linked against libiscsi.
+@item NBD
+QEMU supports NBD (Network Block Devices) both using TCP protocol as well
+as Unix Domain Sockets.
+
+Syntax for specifying a NBD device using TCP
+``nbd:<server-ip>:<port>[:exportname=<export>]''
+
+Syntax for specifying a NBD device using Unix Domain Sockets
+``nbd:unix:<domain-socket>[:exportname=<export>]''
+
+
+Example for TCP
+@example
+qemu --drive file=nbd:192.0.2.1:30000
+@end example
+
+Example for Unix Domain Sockets
+@example
+qemu --drive file=nbd:unix:/tmp/nbd-socket
+@end example
+
+@item Sheepdog
+Sheepdog is a distributed storage system for QEMU.
+QEMU supports using either local sheepdog devices or remote networked
+devices.
+
+Syntax for specifying a sheepdog device
+@table @list
+``sheepdog:<vdiname>''
+
+``sheepdog:<vdiname>:<snapid>''
+
+``sheepdog:<vdiname>:<tag>''
+
+``sheepdog:<host>:<port>:<vdiname>''
+
+``sheepdog:<host>:<port>:<vdiname>:<snapid>''
+
+``sheepdog:<host>:<port>:<vdiname>:<tag>''
+@end table
+
+Example
+@example
+qemu --drive file=sheepdog:192.0.2.1:30000:MyVirtualMachine
+@end example
+
+See also @url{http://http://www.osrg.net/sheepdog/}.
+
@end table
ETEXI
projects / mirror_qemu.git / blobdiff