Re: [PATCH v2 00/19] btrfs zoned block device support

[Naohiro Aota <Naohiro.Aota@wdc.com>]

On 2019/06/13 22:45, David Sterba wrote:> On Thu, Jun 13, 2019 at 04:59:23AM +0000, Naohiro Aota wrote:
>> On 2019/06/13 2:50, David Sterba wrote:
>>> On Fri, Jun 07, 2019 at 10:10:06PM +0900, Naohiro Aota wrote:
>>> How can I test the zoned devices backed by files (or regular disks)? I
>>> searched for some concrete example eg. for qemu or dm-zoned, but closest
>>> match was a text description in libzbc README that it's possible to
>>> implement. All other howtos expect a real zoned device.
>>
>> You can use tcmu-runer [1] to create an emulated zoned device backed by
>> a regular file. Here is a setup how-to:
>> http://zonedstorage.io/projects/tcmu-runner/#compilation-and-installation>> That looks great, thanks. I wonder why there's no way to find that, all
> I got were dead links to linux-iscsi.org or tutorials of targetcli that
> were years old and not working.

Actually, this is quite new site. ;-)

> Feeding the textual commands to targetcli is not exactly what I'd
> expect for scripting, but at least it seems to work.

You can use "targetcli <directory> <command> [<args> ...]" format, so
you can call e.g.

targetcli /backstores/user:zbc create name=foo size=10G cfgstring=model-HM/zsize-256/conv-1@/mnt/nvme/disk0.raw

> I tried to pass an emulated ZBC device on host to KVM guest (as a scsi
> device) but lsscsi does not recognize that it as a zonde device (just a
> QEMU harddisk). So this seems the emulation must be done inside the VM.

Oops, QEMU hide the detail.

In this case, you can try exposing the ZBC device via iSCSI.

On the host:
(after creating the ZBC backstores)
# sudo targetcli /iscsi create
Created target iqn.2003-01.org.linux-iscsi.naota-devel.x8664:sn.f4f308e4892c.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
# TARGET="iqn.2003-01.org.linux-iscsi.naota-devel.x8664:sn.f4f308e4892c"

(WARN: Allow any node to connect without any auth)
# targetcli /iscsi/${TARGET}/tpg1 set attribute generate_node_acls=1
Parameter generate_node_acls is now '1'.
( or you can explicitly allow an initiator)
# TCMU_INITIATOR=iqn.2018-07....
# targecli /iscsi/${TARGET}/tpg1/acls create ${TCMU_INITIATOR}

(for each backend)
# targetcli /iscsi/${TARGET}/tpg1/luns create /backstores/user:zbc/foo
Created LUN 0.

Then, you can login to the iSCSI on the KVM guest like:

# iscsiadm -m discovery -t st -p $HOST_IP
127.0.0.1:3260,1 iqn.2003-01.org.linux-iscsi.naota-devel.x8664:sn.f4f308e4892c
# iscsiadm -m node -l -T ${TARGET}
Logging in to [iface: default, target: iqn.2003-01.org.linux-iscsi.naota-devel.x8664:sn.f4f308e4892c, portal: 127.0.0.1,3260]
Login to [iface: default, target: iqn.2003-01.org.linux-iscsi.naota-devel.x8664:sn.f4f308e4892c, portal: 127.0.0.1,3260] successful.