[RFC] Fiber Channel StoragePool

[Rodrigo Trujillo]

Hi folks,

I am starting to work in this feature, but I did not understand exactly what the project need.
The wiki says:

"""
Create a new FC libvirt storage pool

• Allow for FC target specification.
  
• Associate the target with a storage pool.

"""

As far as I know FC luns are mapped in linux as devices ( /dev/sdX ), and can be mounted normally.
So, is the request related to pass the devices or mounting points to kimchi ? In this case, this is
almost the same that create a Filesystem pool.
So, kinchi would have to check if the filesystem belongs to a FC device.

Thoughts ?

Rodrigo

[Shu Ming]

I think the goal is to achieve a native FC storage pools like iSCSI storage pools and you can reference iSCSI storage pool support patch.  That is, one FC lun can be mapped to one volume in the storage pool which is composed from multiple FC luns exported by the FC storage server.  And a specific volume can be attached to the VM as a block device.   Although, you can create a LVM volume group on a FC lun and then use the volume group as a LVM based storage pool, that is not a native way to support Fibre Channel storage pool because it depends on the lVM technology.   By the way,  "/dev/disk/by-path" should be used instead of "/dev/sdX" for a FC lun device,  because it is persistent while "/dev/sdX" is volatile.

Rodrigo






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[Aline Manera]

It will be a SCSI pool with FC adapter.

For reference:

http://wiki.libvirt.org/page/NPIV_in_libvirt#NPIV_in_libvirt
http://libvirt.org/formatstorage.html (search for 'fc_host')

[Zhou Zheng Sheng]

on 2013/12/10 21:56, Rodrigo Trujillo wrote:
> Hi folks,
>
> I am starting to work in this feature, but I did not understand exactly
> what the project need.
> The wiki says:
>
> """
> Create a new FC libvirt storage pool
>

> * Allow for FC target specification.
> * Associate the target with a storage pool.

>
> """
>
> As far as I know FC luns are mapped in linux as devices ( /dev/sdX ),
> and can be mounted normally.
> So, is the request related to pass the devices or mounting points to
> kimchi ? In this case, this is
> almost the same that create a Filesystem pool.
> So, kinchi would have to check if the filesystem belongs to a FC device.
>
> Thoughts ?
>
> Rodrigo
>

The FC configuration is rather automatic and simple if the HBA card and
switch are installed correctly.
To trigger the FC scan, we usually just run
echo "- - -" > /sys/class/scsi_host/hostX/scan
After the OS scans for FC LUNs, they appear as /dev/sdX. There is no
step like iSCSI login to specific target. In libvirt official
documentation it mentions iSCSI storage pool but not FC pool. Does the
task mean for FCoE?

I think FC mapped /dev/sdX can be used as PVs in a VG, so the tasks "Add
a new local physical disk to a new libvirt storage pool" and "Add a new
local physical disk to an existing libvirt storage pool" should cover it
already. Maybe we can inspect the generated /dev/sdX and collect those
from the specific target and add them to a storage pool, or create a new
logical volume storage pool for them.

--
Thanks and best regards!

Zhou Zheng Sheng / 周征晟
E-mail: zhsh...@linux.vnet.ibm.com
Telephone: 86-10-82454397

[Sheldon]

Does that means, two ways to use the FC luns?
1.
The FC libvirt storage pool, they expose the lun as /dev/sdX, and
install VM on /dev/sdX directly.
2.
mapped /dev/sdX can be used as PVs in a VG. install VM on lvm partition.


For 2,
It seems that patch ”Logical StoragePool - backend support“ can
collect /dev/sdX，
and create a new logical volume storage pool for them.

But there are still some bugs in backend.

Meina is fixing them.






--
Sheldon Feng(冯少合)<sha...@linux.vnet.ibm.com>
IBM Linux Technology Center

[Pradeep K Surisetty]

On Tue, 10 Dec 2013 11:56:45 -0200
Rodrigo Trujillo <rodrigo....@linux.vnet.ibm.com> wrote:

> Hi folks,
>
> I am starting to work in this feature, but I did not understand
> exactly what the project need.
> The wiki says:
>
> """
> Create a new FC libvirt storage pool
>

> * Allow for FC target specification.
> * Associate the target with a storage pool.

>
> """
>
> As far as I know FC luns are mapped in linux as devices ( /dev/sdX ),
> and can be mounted normally.
> So, is the request related to pass the devices or mounting points to
> kimchi ? In this case, this is
> almost the same that create a Filesystem pool.
> So, kinchi would have to check if the filesystem belongs to a FC
> device.
>
> Thoughts ?

Dependency is ISCSI pool support. Then comes FC support next.
Who is looking at ISCSI??

--Pradeep

[Pradeep K Surisetty]

On Wed, 11 Dec 2013 19:52:43 +0530
Pradeep K Surisetty <psur...@linux.vnet.ibm.com> wrote:

> On Tue, 10 Dec 2013 11:56:45 -0200
> Rodrigo Trujillo <rodrigo....@linux.vnet.ibm.com> wrote:
>
> > Hi folks,
> >
> > I am starting to work in this feature, but I did not understand
> > exactly what the project need.
> > The wiki says:
> >
> > """
> > Create a new FC libvirt storage pool
> >
> > * Allow for FC target specification.
> > * Associate the target with a storage pool.
> >
> > """
> >
> > As far as I know FC luns are mapped in linux as devices ( /dev/sdX
> > ), and can be mounted normally.
> > So, is the request related to pass the devices or mounting points
> > to kimchi ? In this case, this is
> > almost the same that create a Filesystem pool.
> > So, kinchi would have to check if the filesystem belongs to a FC
> > device.
> >

Lets say. your KVM node attached to v7000 storage with FC
suported HBA card & FC cable. You create a volume on v7000 and map it
to specific KVM node. From virt-manager, you can find this volume listed under ISCSI pool.
FC pool is subset of ISCSI pool.
There is no much work involved for FC pool

Your voulme will be listed on kvm host as shown below.
/dev/disk/by-id/wwn-0x600507680280865df800000000000060

>
> --Pradeep
>

[Aline Manera]

From libvirt doc the FC pool is related to SCSI pool (not with iSCSI pool)

See: http://libvirt.org/storage.html#StorageBackendISCSI

>> --Pradeep
>>

[Pradeep K Surisetty]

On Wed, 18 Dec 2013 01:03:39 -0200
Aline Manera <ali...@linux.vnet.ibm.com> wrote:


>
> From libvirt doc the FC pool is related to SCSI pool (not with iSCSI
> pool)
>

My mistake. I meant SCSI pool.

> See: http://libvirt.org/storage.html#StorageBackendISCSI
>
> >> --Pradeep
> >>
>