[Gluster-users] how well will this work

[William Muriithi]

Thanks Joe,

>> Isn't there a 1:1 relationship between brick and server?
> In my configuration, 1 server has 4 drives (well, 5, but one's the OS).
> Each drive has one gpt partition. I create an lvm volume group that
> holds all four huge partitions. For any one GlusterFS volume I create 4
> lvm logical volumes:
>
> lvcreate -n a_vmimages clustervg /dev/sda1
> lvcreate -n b_vmimages clustervg /dev/sdb1
> lvcreate -n c_vmimages clustervg /dev/sdc1
> lvcreate -n d_vmimages clustervg /dev/sdd1
>
> then format them xfs and (I) mount them under
> /data/glusterfs/vmimages/{a,b,c,d}. These four lvm partitions are bricks
> for the new GlusterFS volume.
Followed, actually, going to redo it this way, but will or a RAID
instead of individual drive.  Thanks
>
> As glusterbot would say if asked for the glossary:
>> A "server" hosts "bricks" (ie. server1:/foo) which belong to a
>> "volume"  which is accessed from a "client".
>
Yes, checked the manual glossary and its well explained.  Had yet to
read those last pages
> My volume would then look like
> gluster volume create replica 3
> server{1,2,3}:/data/glusterfs/vmimages/a/brick
> server{1,2,3}:/data/glusterfs/vmimages/b/brick
> server{1,2,3}:/data/glusterfs/vmimages/c/brick
> server{1,2,3}:/data/glusterfs/vmimages/d/brick
>>> Each vm image is only 6 gig, enough for the operating system and
>>> applications and is hosted on one volume. The data for each application
>>> is hosted on its own GlusterFS volume.
>> Hmm, petty good idea, especially security wise.  Means one VM can not
>> mess with another vm files.  Is it possible to extend gluster volume
>> without destroying and recreating it with bigger peer storage setting
> I can do that two ways. I can add servers with storage and then
> add-brick to expand, or I can resize the lvm partitions and grow xfs
> (which I have done live several times).
Will be going with lvm, now that I understand what is a brick
>
>>> For mysql, I set up my innodb store to use 4 files (I don't do 1 file
>>> per table), each file distributes to each of the 4 replica subvolumes.
>>> This balances the load pretty nicely.
> It's not so much a "how glusterfs works" question as much as it is a how
> innodb works question. By configuring the innodb_data_file_path to start
> with a multiple of your bricks (and carefully choosing some filenames to
> ensure they're distributed evenly), records seem to be (and I only have
> tested this through actual use and have no idea if this is how it's
> supposed to work) accessed evenly over the distribute set.
>
Hmm, have you checked on the gluster servers that these four files are
in separate bricks?  As far as I understand, if you have not done
anything Glusterfs scheduler (Default ALU on version 3.3), it is
likely that is not whats happening. Or you are using a version that
has a different scheduler.  Interesting though.  Poke around and
update us please


Thanks

William