Hi Sage,Community ,
I am unable to use 2 directories to direct data to 2 different
pools. I did following expt.
Created 2 pool "host" & "ghost" to seperate data placement .
--------------------------------------------------//crushmap file
-------------------------------------------------------
# begin crush map
# devices
device 0 osd.0
device 1 osd.1
device 2 osd.2
device 3 osd.3
# types
type 0 osd
type 1 host
type 2 rack
type 3 row
type 4 room
type 5 datacenter
type 6 pool
type 7 ghost
# buckets
host hemantone-mirror-virtual-machine {
id -6 # do not change unnecessarily
# weight 1.000
alg straw
hash 0 # rjenkins1
item osd.2 weight 1.000
}
host hemantone-virtual-machine {
id -7 # do not change unnecessarily
# weight 1.000
alg straw
hash 0 # rjenkins1
item osd.1 weight 1.000
}
rack one {
id -2 # do not change unnecessarily
# weight 2.000
alg straw
hash 0 # rjenkins1
item hemantone-mirror-virtual-machine weight 1.000
item hemantone-virtual-machine weight 1.000
}
ghost hemant-virtual-machine {
id -4 # do not change unnecessarily
# weight 1.000
alg straw
hash 0 # rjenkins1
item osd.0 weight 1.000
}
ghost hemant-mirror-virtual-machine {
id -5 # do not change unnecessarily
# weight 1.000
alg straw
hash 0 # rjenkins1
item osd.3 weight 1.000
}
rack two {
id -3 # do not change unnecessarily
# weight 2.000
alg straw
hash 0 # rjenkins1
item hemant-virtual-machine weight 1.000
item hemant-mirror-virtual-machine weight 1.000
}
pool default {
id -1 # do not change unnecessarily
# weight 4.000
alg straw
hash 0 # rjenkins1
item one weight 2.000
item two weight 2.000
}
# rules
rule data {
ruleset 0
type replicated
min_size 1
max_size 10
step take default
step take one
step chooseleaf firstn 0 type host
step emit
}
rule metadata {
ruleset 1
type replicated
min_size 1
max_size 10
step take default
step take one
step chooseleaf firstn 0 type host
step emit
}
rule rbd {
ruleset 2
type replicated
min_size 1
max_size 10
step take default
step take one
step chooseleaf firstn 0 type host
step emit
}
rule forhost {
ruleset 3
type replicated
min_size 1
max_size 10
step take default
step take one
step chooseleaf firstn 0 type host
step emit
}
rule forghost {
ruleset 4
type replicated
min_size 1
max_size 10
step take default
step take two
step chooseleaf firstn 0 type ghost
step emit
}
# end crush map
------------------------------------------------------------------------------------------------------------------------
1) set replication factor to 2. and crushrule accordingly . ( "host"
got crush_ruleset = 3 & "ghost" pool got crush_ruleset = 4).
2) Now I mounted data to dir. using "mount.ceph 10.72.148.245:6789:/
/home/hemant/x" & "mount.ceph 10.72.148.245:6789:/ /home/hemant/y"
3) then "mds add_data_pool 5" & "mds add_data_pool 6" ( here pool id
are host = 5, ghost = 6)
4) "cephfs /home/hemant/x set_layout --pool 5 -c 1 -u 4194304 -s
4194304" & "cephfs /home/hemant/y set_layout --pool 6 -c 1 -u 4194304
-s 4194304"
PROBLEM:
$ cephfs /home/hemant/x show_layout
layout.data_pool: 6
layout.object_size: 4194304
layout.stripe_unit: 4194304
layout.stripe_count: 1
cephfs /home/hemant/y show_layout
layout.data_pool: 6
layout.object_size: 4194304
layout.stripe_unit: 4194304
layout.stripe_count: 1
Both dir are using same pool to place data even after I specified to
use separate using "cephfs" cmd.
Please help me figure this out.
-
Hemant Surale.
On Thu, Nov 29, 2012 at 3:45 PM, hemant surale <[email protected]> wrote:
>>> does 'ceph mds dump' list pool 3 in teh data_pools line?
>
> Yes. It lists the desired poolids I wanted to put data in.
>
>
> ---------- Forwarded message ----------
> From: hemant surale <[email protected]>
> Date: Thu, Nov 29, 2012 at 2:59 PM
> Subject: Re: OSD daemon changes port no
> To: Sage Weil <[email protected]>
>
>
> I used a little different version of "cephfs" as "cephfs
> /home/hemant/a set_layout --pool 3 -c 1 -u 4194304 -s 4194304"
> and "cephfs /home/hemant/b set_layout --pool 5 -c 1 -u 4194304 -s 4194304".
>
>
> Now cmd didnt showed any error but When I put data to dir "a" & "b"
> ideally it should go to different pool but its not working as of now.
> Whatever I am doing is it possible (to use 2 dir pointing to 2
> different pools for data placement) ?
>
>
>
> -
> Hemant Surale.
>
> On Tue, Nov 27, 2012 at 10:21 PM, Sage Weil <[email protected]> wrote:
>> On Tue, 27 Nov 2012, hemant surale wrote:
>>> I did "mkdir a " "chmod 777 a" . So dir "a" is /home/hemant/a" .
>>> then I used "mount.ceph 10.72.148.245:/ /ho
>>>
>>> root@hemantsec-virtual-machine:/home/hemant# cephfs /home/hemant/a
>>> set_layout --pool 3
>>> Error setting layout: Invalid argument
>>
>> does 'ceph mds dump' list pool 3 in teh data_pools line?
>>
>> sage
>>
>>>
>>> On Mon, Nov 26, 2012 at 9:56 PM, Sage Weil <[email protected]> wrote:
>>> > On Mon, 26 Nov 2012, hemant surale wrote:
>>> >> While I was using "cephfs" following error is observed -
>>> >> ------------------------------------------------------------------------------------------------
>>> >> root@hemantsec-virtual-machine:~# cephfs /mnt/ceph/a --pool 3
>>> >> invalid command
>>> >
>>> > Try
>>> >
>>> > cephfs /mnt/ceph/a set_layout --pool 3
>>> >
>>> > (set_layout is the command)
>>> >
>>> > sage
>>> >
>>> >> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]>
>>> >> >> >> 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 <[email protected]>
>>> >> >> >> >> 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
>>> >> >> >> >> --
>>> >> >> >> >> To unsubscribe from this list: send the line "unsubscribe
>>> >> >> >> >> ceph-devel" in
>>> >> >> >> >> the body of a message to [email protected]
>>> >> >> >> >> More majordomo info at
>>> >> >> >> >> http://vger.kernel.org/majordomo-info.html
>>> >> >> >> >>
>>> >> >> >> >>
>>> >> >> >>
>>> >> >> >>
>>> >> >>
>>> >> >>
>>> >>
>>> >>
>>>
>>>
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