Re: [Qemu-devel] [PATCH] Documentation: Add section about iSCSI LUNS to qemu-doc

[Stefan Weil <sw@weilnetz.de>]

Hi,

I have only some small remarks, see my inline comments below.

Am 11.11.2011 22:46, schrieb Ronnie Sahlberg:
> Add a new section about using iSCSI LUNs with qemu
> and provide a short example on how to set up a target and access it
> using the built-in initiator
>
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
> ---
> qemu-doc.texi | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 53 insertions(+), 0 deletions(-)
>
> diff --git a/qemu-doc.texi b/qemu-doc.texi
> index 149e9bd..c1b293e 100644
> --- a/qemu-doc.texi
> +++ b/qemu-doc.texi
> @@ -421,6 +421,7 @@ snapshots.
> * disk_images_fat_images:: Virtual FAT disk images
> * disk_images_nbd:: NBD access
> * disk_images_sheepdog:: Sheepdog disk images
> +* disk_images_iscsi:: iSCSI LUNs
> @end menu
>
> @node disk_images_quickstart
> @@ -695,6 +696,58 @@ qemu-img create 
> sheepdog:@var{hostname}:@var{port}:@var{image} @var{size}
> qemu sheepdog:@var{hostname}:@var{port}:@var{image}
> @end example
>
> +@node disk_images_iscsi
> +@subsection iSCSI LUNs
> +
> +iSCSI is a popular protocol used to access SCSI devices across a computer
> +network.
> +
> +There are two different ways iSCSI devices can be used by QEMU.
> +
> +The first method is to mount the iSCSI LUN on the host, and make it 
> appear as
> +any other ordinary SCSI device on the host and then to access this 
> device as a
> +/dev/sd device from QEMU. How to do this differs between host OSes.
> +
> +The second method involves using the iSCSI initiator that is built into
> +QEMU. This provides a mechanism that works the same way regardless of 
> which
> +host OS you are running QEMU on. This section will describe this 
> second method
> +of using iSCSI together with QEMU.
> +
> +In QEMU, iSCSI devices are described using special iSCSI URLs
> +
> +@example
> +URL syntax:
> +iscsi://[<username>[%<password>]@@]<host>[:<port>]/<target-iqn-name>/<lun>
> +@end example
> +
> +Username and password are optional and only used if your taget is set up

taget -> target

> +using CHAP authentication for access control.
> +Alternatively the username and passwords can also be set via environment

password instead of passwords?

> +variables to have these not show up in the process list
> +
> +@example
> +export LIBISCSI_CHAP_USERNAME=<username>
> +export LIBISCSI_CHAP_PASSWORD=<password>
> +iscsi://<host>/<target-iqn-name>/<lun>
> +@end example
> +
> +Howto set up a simple iSCSI target on loopback and accessing it via QEMU:
> +@example
> +Setting up a iSCSI target with one CDROM and one DISK:
> +tgtd --iscsi portal=127.0.0.1:3260
> +tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.qemu.test
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 \
> + -b /IMAGES/disk.img --device-type=disk
> +tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 2 \
> + -b /IMAGES/cd.iso --device-type=cd
> +tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
> +
> +qemu -boot d -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \

There is no qemu executable any longer. You may choose from
a large number of executable names, e.g. qemu-system-i386.

> + -cdrom iscsi://127.0.0.1/iqn.qemu.test/2
> +@end example
> +
> +
> +
> @node pcsys_network
> @section Network emulation

Thanks for providing this documentation.

Kind regards,

Stefan Weil