On 05/26/2014 06:55 AM, Haomai Wang wrote:
On Mon, May 26, 2014 at 9:46 AM, Guang Yang <[email protected]> wrote:
Hello Haomai,
We are evaluating the key-value store backend which comes along with Firefly
release (thanks for implementing it in Ceph), it is very promising for a couple
of our use cases, after going through the related code change, I have a couple
of questions which needs your help:
1. One observation is that, for object larger than 1KB, it will be striped
to multiple chunks (k-v in the leveldb table), with one strip as 1KB size. Is
there any particular reason we choose 1KB as the strip size (and I didn’t find
a configuration to tune this value)?
1KB is not a serious value, this value can be configured in the near future.
So that is currently hardcoded? I can't find any reference to it in
config_opts.h
2. This is properly a leveldb question, do we expect performance degradation
as the leveldb instance keeps increasing (e.g. several TB)?
Ceph OSD is expected to own a physical disk, normally is several
TB(1-4TB). LevelDB can take it easy. Especially we use it to store
large value(compared to normal application usage).
With a large value you mean something like 4MB? The regular strip-size
for RBD, CephFS and such?
Thanks,
Guang
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Wido den Hollander
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