diff options
Diffstat (limited to 'qemu-options.hx')
| -rw-r--r-- | qemu-options.hx | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index 03e95fd2bf..cea9b72b2a 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -118,8 +118,9 @@ ETEXI DEF("drive", HAS_ARG, QEMU_OPTION_drive, "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" " [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n" - " [,cache=writethrough|writeback|none][,format=f][,serial=s]\n" - " [,addr=A][,id=name][,aio=threads|native][,readonly=on|off]\n" + " [,cache=writethrough|writeback|unsafe|none][,format=f]\n" + " [,serial=s][,addr=A][,id=name][,aio=threads|native]\n" + " [,readonly=on|off]\n" " use 'file' as a drive image\n", QEMU_ARCH_ALL) STEXI @item -drive @var{option}[,@var{option}[,@var{option}[,...]]] @@ -148,7 +149,7 @@ These options have the same definition as they have in @option{-hdachs}. @item snapshot=@var{snapshot} @var{snapshot} is "on" or "off" and allows to enable snapshot for given drive (see @option{-snapshot}). @item cache=@var{cache} -@var{cache} is "none", "writeback", or "writethrough" and controls how the host cache is used to access block data. +@var{cache} is "none", "writeback", "unsafe", or "writethrough" and controls how the host cache is used to access block data. @item aio=@var{aio} @var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO. @item format=@var{format} @@ -180,6 +181,12 @@ Some block drivers perform badly with @option{cache=writethrough}, most notably, qcow2. If performance is more important than correctness, @option{cache=writeback} should be used with qcow2. +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, +etc. you're image will most probably be rendered unusable. + Instead of @option{-cdrom} you can use: @example qemu -drive file=file,index=2,media=cdrom |