hi
i'm testing on rbd image. the are TWO questions that confused me.
ceph -v
ceph version 10.2.10 (5dc1e4c05cb68dbf62ae6fce3f0700e4654fdbbe)
ceph version 10.2.10 (5dc1e4c05cb68dbf62ae6fce3f0700e4654fdbbe)
uname -r
3.10.0-514.el7.x86_64
3.10.0-514.el7.x86_64
(1) does rbd image supports multiple clients to write data simultaneously? if it supports, how can share data between several clients using rbd image?
client A: write data to rbd/test
client B: rbd map, and mount it to /mnt, file can be found in /mnt dir, but the content is miss.
on monitor:
rbd create rbd/test -s 1024
rbd info rbd/test
rbd image 'test':
size 1024 MB in 256 objects
order 22 (4096 kB objects)
block_name_prefix: rbd_data.121d238e1f29
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
flags:
rbd image 'test':
size 1024 MB in 256 objects
order 22 (4096 kB objects)
block_name_prefix: rbd_data.121d238e1f29
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
flags:
then i disble the feature: object-map, fast-diff, deep-flatten
on client A:
rbd map rbd/test
mkfs -t xfs /dev/rbd0
mount /dev/rbd/rbd/test /mnt/
echo 124 > /mnt/host124
cat host124
124
124
on client B:
rbd map rbd/test
mount /dev/rbd/rbd/test /mnt/
cat host124 --> show nothing!
echo 125 > /mnt/host125
cat /mnt/host125
125
125
then on client C:
rbd map rbd/test
mount /dev/rbd/rbd/test /mnt/
cd /mnt
cat host124 --> show nothing!
cat host125 --> show nothing!
(2) does rbd image supports stripping? if does, howto?
on monitor, i create an image as following:
rbd create rbd/test --image-feature layering,striping,exclusive-lock --size 1024 --object-size 4096 --stripe-unit 4096 --stripe-count 2
stripe unit is not a factor of the object size
stripe unit is not a factor of the object size
rbd create rbd/test --image-feature layering,striping,exclusive-lock --size 1024 --object-size 8M --stripe-unit 4M --stripe-count 2
rbd: the argument ('4M') for option '--unit' is invalid
rbd: the argument ('4M') for option '--unit' is invalid
i don't know why those cmd fails?
finally, i successed with the following cmd:
rbd create rbd/test --image-feature layering,striping,exclusive-lock --size 1024 --object-size 8388608 --stripe-unit 4194304 --stripe-count 2
but whe i map it on client, it fails.
the error msg:
rbd: image test: unsupported stripe unit (got 4194304 want 8388608)
best wishes
thanks
13605702596@xxxxxxx
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