[Pvfs2-users] Re: Multiple data stores on one machine

[Steve]

Thanks Murali,
 
Yes indeed I have two separate storage files, an error in my email, sorry. I
should have pasted both parts rather than duplicate and edit from memory. 
 
For clarity I have
/pvfs2-storage-space 
/pvfs2-storage-space2
 
Do the ranges have to be in some proportions to the disk size used ? 
 
steve
 
-------Original Message------- 
 
From: Murali Vilayannur 
Date: 12/01/2007 17:55:08 
To: Steve 
Cc: pvfs2-users at beowulf-underground.org; Greg Kurtzer 
Subject: Re: Multiple data stores on one machine 
 
Hi Steve, 
 
Looks good. See inline comments below... 
 
> <Aliases> 
> Alias caos1 TCP://caos:3334 
> Alias caos2 TCP://caos:3335 
> </Aliases> 
> <Filesystem> 
> Name pvfs2-fs 
> ID 699094865 
> RootHandle 1048576 
> <MetaHandleRanges> 
> Range caos1 4-214748365> 
> </MetaHandleRanges> 
> 
> <DataHandleRanges> 
> 
> Range caos1 2147483651-4294967297 
> 
> Range caos2 4294967298-6442450944 
> 
> </DataHandleRanges> 
> 
> <StorageHints> 
> 
> TroveSyncMeta yes 
> 
> TroveSyncData no 
> 
> </StorageHints> 
> 
> </Filesystem> 
> 
> 
> 
> /etc/pvfs2-server.conf-caos1 
> 
> StorageSpace /pvfs2-storage-space 
 
(^) See the comment on why it is a bad idea to share storage spaces below...

 
> 
> HostID "TCP://caos:3334" 
> 
> LogFile /tmp/pvfs2-server.log 
> 
> 
> 
> /etc/pvfs2-server.conf-caos2 
> 
> StorageSpace /pvfs2-storage-space 
 
^^^^^^^^ 
Please don't use the same storage space for 2 different pvfs2-server 
Processes on the same node! They may end up trampling over each other. 
I thought the whole point of what you were trying to do was to add 
Some new storage space/drives to the pvfs2 volume!! :) 
> 
> Pvfs2-server /etc/pvfs2-fs.conf /etc/pvfs2-server.conf-caos1 -f 
> 
> Pvfs2-server /etc/pvfs2-fs.conf /etc/pvfs2-server.conf-caos2 -f 
> 
> 
> 
> Then started 2 servers 
> 
> 
> 
> Pvfs2-server /etc/pvfs2-fs.conf /etc/pvfs2-server.conf-caos1 
> 
> Pvfs2-server /etc/pvfs2-fs.conf /etc/pvfs2-server.conf-caos2 
> 
> 
> 
> Is that correct that I need to run 2 server daemons ? 
 
Yes! Running both the daemons is correct.. 
 
> The mount command then seems a little confusing 
> 
> Mount -t pvfs2 TCP://caos:3334/pvfs2-fs /mnt/pvfs2 
> 
> As you only reference one port. 
 
This is probably documented somewhere, but it is possible to use any 
Of the servers for mounting!! 
All you need to pass is a valid bmi URL for a valid config server, so 
In this case 
Mount -t pvfs2 TCP://caos:3335/pvfs2-fs /mnt/pvfs2 
Would also have worked fine. 
 
> In this instance I started with genconfig editing the files to get a 
> starting point. Can you explain the numbers and how a would choose the
range 
> to add another files store ? Is it a simple as calculating the difference 
> from one range and adding that to last one used ? 
 
Yes it is! Just make sure that no handle ranges overlap with each other. 
For fairness, it would be best if all servers see roughly the same # 
Of handle ranges 
So that the handle allocator can fairly disperse the handles to all the
servers. 
Hope this explains all your questions, 
Thanks, 
Murali 
 
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