Hi Dan,
Yes once a zpool is created there is a way we can use the zpool and
make a partition out of it using "zfs create -V". The newly created
partition will be available on fdisk. Later the same partition can be
formatted with ext4 and used with ceph-osd.
I have also tried using a zfs filesystem in the zpool and mapped it
with osd. When i run mkcephfs i get "error creating empty object store
/osd.0: (22) invalid argument
== osd.0 ===
2012-10-27 10:40:33.939961 7f6e6165d780 -1 filestore(/osd.0) mkjournal
error creating journal on /osd.0/journal: (22) Invalid argument
2012-10-27 10:40:33.939981 7f6e6165d780 -1 OSD::mkfs: FileStore::mkfs
failed with error -22
2012-10-27 10:40:33.940036 7f6e6165d780 -1 ** ERROR: error creating
empty object store in /osd.0: (22) Invalid argument
failed: '/sbin/mkcephfs -d /tmp/mkcephfs.3zqOx7Btvl --init-daemon
osd.0'
---
Regards,
Raghunandhan.G
IIHT Cloud Solutions Pvt. Ltd.
#15, 4th Floor, 'A' Wing, Sri Lakshmi Complex,
St. Marks Road, Bangalore - 560 001, India
On 27-10-2012 02:08, Dan Mick wrote:
On 10/25/2012 09:46 PM, Raghunandhan wrote:
Hi Sage,
Thanks for replying back, Once a zpool is created if i mount it on
/var/lib/ceph/osd/ceph-0 the cephfs doesnt recognize it as a
superblock
and hence it fails,
I assume you mean "once a zfs is created"? One can't mount zpools,
can one?
Im trying to build this on our cloud storage since
btrfs has not been stable nor they have come up with online dedup i
have
no other choice for now to work with zfs ceph which makes sense.
So what i exactly did was created a zpool store
1 Then used the same store and made a block device from it using zfs
create
2 Once the zfs create was successful i was able to format with ext4
using xattr
3 On top of it was the ceph
Following this process doesnt make sense because of multiple layer
on
the storage and the ceph consumes a lot of RAM and cpu cycles which
ends
up in kernel hung task. It would be great if there is a way i could
directly use the zfs pool with ceph and make it work.
Have you actually tried making a zfs filesystem in the zpool, and
using that as backing store for the osd?
---
Regards,
Raghunandhan.G
IIHT Cloud Solutions Pvt. Ltd.
#15, 4th Floor, 'A' Wing, Sri Lakshmi Complex,
St. Marks Road, Bangalore - 560 001, India
On 25-10-2012 22:06, Sage Weil wrote:
[moved to ceph-devel]
On Thu, 25 Oct 2012, Raghunandhan wrote:
Hi All,
I have been working around ceph quite a long and trying to stitch
zfs
with
ceph. I was able to do it to certain extent as follows:
1. zpool creation
2. set dedup
3. create a mountable volume of zfs (zfs create)
4. format the volume with ext4 and enabling xattr
5. mkcephfs on the volume
This actually works and dedup is perfect. But i need to avoid
multiple layers
on the storage since the performance is very slow and the kernel
timeout
occurs often for a 8GB RAM. I want to test the performance between
btrfs and
zfs. I want to avoid the above multiple layering on storage and
make
the ceph
cluster aware of zfs. Let me know if anyone has workaround this.
I'm not familiar enough with zfs to know what 'mountable volume'
means..
is that a block device/lun that you're putting ext4 on? Probably
the
best
results will come from creating a zfs *file system* (using the ZPL
or
whatever it is) and running ceph-osd on top of that.
There is at least one open bug from someone having problems there,
but
we'd very much like to sort out the problem.
sage
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