my trials :
cephfs /mnt/ceph/a --pool 3 // not working
cephfs /home/hemant/a -p 3 // not working
cpehfs /home/hemant/a set_layout --pool 3 // not working
I mounted data on "/home/hemant/a" first then Used cephfs cmd.
Please help me figure out the way.
Regards,
Hemant Surale.
On Mon, Nov 26, 2012 at 4:09 PM, hemant surale <hemant.surale@xxxxxxxxx> wrote:
> While I was using "cephfs" following error is observed -
> ------------------------------------------------------------------------------------------------
> root@hemantsec-virtual-machine:~# cephfs /mnt/ceph/a --pool 3
> invalid command
> usage: cephfs path command [options]*
> Commands:
> show_layout -- view the layout information on a file or dir
> set_layout -- set the layout on an empty file,
> or the default layout on a directory
> show_location -- view the location information on a file
> Options:
> Useful for setting layouts:
> --stripe_unit, -u: set the size of each stripe
> --stripe_count, -c: set the number of objects to stripe across
> --object_size, -s: set the size of the objects to stripe across
> --pool, -p: set the pool to use
>
> Useful for getting location data:
> --offset, -l: the offset to retrieve location data for
>
> ------------------------------------------------------------------------------------------------
> It may be silly question but unable to figure it out.
>
> :(
>
>
>
>
> On Wed, Nov 21, 2012 at 8:59 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>> On Wed, 21 Nov 2012, hemant surale wrote:
>>> > Oh I see. Generally speaking, the only way to guarantee separation is to
>>> > put them in different pools and distribute the pools across different sets
>>> > of OSDs.
>>>
>>> yeah that was correct approach but i found problem doing so from
>>> abstract level i.e. when I put file inside mounted dir
>>> "/home/hemant/cephfs " ( mounted using "mount.ceph" cmd ) . At that
>>> time anyways ceph is going to use default pool data to store files (
>>> here files were striped into different objects and then sent to
>>> appropriate osd ) .
>>> So how to tell ceph to use different pools in this case ?
>>>
>>> Goal : separate read and write operations , where read will be done
>>> from one group of OSD and write is done to other group of OSD.
>>
>> First create the other pool,
>>
>> ceph osd pool create <name>
>>
>> and then adjust the CRUSH rule to distributed to a different set of OSDs
>> for that pool.
>>
>> To allow cephfs use it,
>>
>> ceph mds add_data_pool <poolid>
>>
>> and then:
>>
>> cephfs /mnt/ceph/foo --pool <poolid>
>>
>> will set the policy on the directory such that new files beneath that
>> point will be stored in a different pool.
>>
>> Hope that helps!
>> sage
>>
>>
>>>
>>>
>>>
>>>
>>> -
>>> Hemant Surale.
>>>
>>>
>>> On Wed, Nov 21, 2012 at 12:33 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>>> > On Wed, 21 Nov 2012, hemant surale wrote:
>>> >> Its a little confusing question I believe .
>>> >>
>>> >> Actually there are two files X & Y. When I am reading X from its
>>> >> primary .I want to make sure simultaneous writing of Y should go to
>>> >> any other OSD except primary OSD for X (from where my current read is
>>> >> getting served ) .
>>> >
>>> > Oh I see. Generally speaking, the only way to guarantee separation is to
>>> > put them in different pools and distribute the pools across different sets
>>> > of OSDs. Otherwise, it's all (pseudo)random and you never know. Usually,
>>> > they will be different, particularly as the cluster size increases, but
>>> > sometimes they will be the same.
>>> >
>>> > sage
>>> >
>>> >
>>> >>
>>> >>
>>> >> -
>>> >> Hemant Sural.e
>>> >>
>>> >> On Wed, Nov 21, 2012 at 11:50 AM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>>> >> > On Wed, 21 Nov 2012, hemant surale wrote:
>>> >> >> >> and one more thing how can it be possible to read from one osd and
>>> >> >> >> then simultaneous write to direct on other osd with less/no traffic?
>>> >> >> >
>>> >> >> > I'm not sure I understand the question...
>>> >> >>
>>> >> >> Scenario :
>>> >> >> I have written file X.txt on some osd which is primary for filr
>>> >> >> X.txt ( direct write operation using rados cmd) .
>>> >> >> Now while read on file X.txt is in progress, Can I make sure
>>> >> >> the simultaneous write request must be directed to other osd using
>>> >> >> crushmaps/other way?
>>> >> >
>>> >> > Nope. The object location is based on the name. Reads and writes go to
>>> >> > the same location so that a single OSD can serialize request. That means,
>>> >> > for example, that a read that follows a write returns the just-written
>>> >> > data.
>>> >> >
>>> >> > sage
>>> >> >
>>> >> >
>>> >> >> Goal of task :
>>> >> >> Trying to avoid read - write clashes as much as possible to
>>> >> >> achieve faster operations (I/O) . Although CRUSH selects osd for data
>>> >> >> placement based on pseudo random function. is it possible ?
>>> >> >>
>>> >> >>
>>> >> >>
>>> >> >> -
>>> >> >> Hemant Surale.
>>> >> >>
>>> >> >>
>>> >> >>
>>> >> >> On Tue, Nov 20, 2012 at 10:15 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
>>> >> >> > On Tue, 20 Nov 2012, hemant surale wrote:
>>> >> >> >> Hi Community,
>>> >> >> >> I have question about port number used by ceph-osd daemon . I
>>> >> >> >> observed traffic (inter -osd communication while data ingest happened)
>>> >> >> >> on port 6802 and then after some time when I ingested second file
>>> >> >> >> after some delay port no 6804 was used . Is there any specific reason
>>> >> >> >> to change port no here?
>>> >> >> >
>>> >> >> > The ports are dynamic. Daemons bind to a random (6800-6900) port on
>>> >> >> > startup and communicate on that. They discover each other via the
>>> >> >> > addresses published in the osdmap when the daemon starts.
>>> >> >> >
>>> >> >> >> and one more thing how can it be possible to read from one osd and
>>> >> >> >> then simultaneous write to direct on other osd with less/no traffic?
>>> >> >> >
>>> >> >> > I'm not sure I understand the question...
>>> >> >> >
>>> >> >> > sage
>>> >> >> --
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>>> >> >>
>>> >> >>
>>> >>
>>> >>
>>>
>>>
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