Le 21/10/2014 09:31, Nicheal a écrit :
> 2014-10-21 7:40 GMT+08:00 Lionel Bouton :
>> Hi,
>>
>> Le 21/10/2014 01:10, 池信泽 a écrit :
>>
>> Thanks.
>>
>>Another reason is the checksum in the attr of object used for deep scrub
>> in EC pools should be computed when modify the object. When supportin
2014-10-20 22:39 GMT+08:00 Wido den Hollander :
> On 10/20/2014 03:25 PM, 池信泽 wrote:
>> hi, cephers:
>>
>> When I look into the ceph source code, I found the erasure code pool
>> not support
>> the random write, it only support the append write. Why? Is that random
>> write of is erasure code
2014-10-21 7:40 GMT+08:00 Lionel Bouton :
> Hi,
>
> Le 21/10/2014 01:10, 池信泽 a écrit :
>
> Thanks.
>
>Another reason is the checksum in the attr of object used for deep scrub
> in EC pools should be computed when modify the object. When supporting the
> random write, We should caculate the whol
Hi,
Le 21/10/2014 01:10, 池信泽 a écrit :
> Thanks.
>
>Another reason is the checksum in the attr of object used for deep
> scrub in EC pools should be computed when modify the object. When
> supporting the random write, We should caculate the whole object for
> checksum, even if there is a bit m
Thanks.
Another reason is the checksum in the attr of object used for deep scrub
in EC pools should be computed when modify the object. When supporting the
random write, We should caculate the whole object for checksum, even if
there is a bit modified. If only supporting append write, We can ge
Le 20/10/2014 16:39, Wido den Hollander a écrit :
> On 10/20/2014 03:25 PM, 池信泽 wrote:
>> hi, cephers:
>>
>> When I look into the ceph source code, I found the erasure code pool
>> not support
>> the random write, it only support the append write. Why? Is that random
>> write of is erasure co
Hi 池信泽,
On 20/10/2014 06:25, 池信泽 wrote:> hi, cephers:
>
> When I look into the ceph source code, I found the erasure code pool
> not support
> the random write, it only support the append write. Why?
The main reason is because it is complicated. The second reason is that it as a
signif
On 10/20/2014 03:25 PM, 池信泽 wrote:
> hi, cephers:
>
> When I look into the ceph source code, I found the erasure code pool
> not support
> the random write, it only support the append write. Why? Is that random
> write of is erasure code high cost and the performance of the deep scrub is
> v
This is a common constraint in many erasure coding storage system. It
arises because random writes turn into a read-modify-write cycle (in order
to redo the parity calculations). So we simply disallow them in EC pools,
which works fine for the target use cases right now.
-Greg
On Monday, October 2
hi, cephers:
When I look into the ceph source code, I found the erasure code pool
not support
the random write, it only support the append write. Why? Is that random
write of is erasure code high cost and the performance of the deep scrub is
very poor?
Thanks.
_
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