Shared Qfs metadata server question
Hi,
I hope this is the right place ( I looked around ). We have a Shared QFS installation.3 280r's, shareing/servering webdata. Everything has been running extermely well, untill today.
The metadata server shutdown ( logs say button pressed ), without the metadata server up, the other two systems stopped being able to use the shared FS. This brings our web presence down. We have a loadbalancer in place for redunancy for the webservers , so its a little useless if there is still one point of failure.
So the question is can you have two ( or a standby ) metadata servers running with QFS?
Thanks,
Tom de - still checking the docs at docs.sun.com
[698 byte] By [
] at [2007-11-25 23:01:45]
# 1
Have you looked at this:
<a href="http://www.sun.com/products-n-solutions/hardware/docs/pdf/819-1550-10.pdf " target="_blank"> http://www.sun.com/products-n-solutions/hardware/docs/pdf/81 9-1550-10.pdf</a>
Page 91.
<i>You can configure more than one host as a potential metadata server, but only one host can be the metadata server at any one time.</i>
at 2007-7-5 17:51:09 >
# 2
Thanks, even tho its manual change over it will work for us. I was hoping for a auto solution :)Tom de
at 2007-7-5 17:51:09 >
# 3
You can have two MDS servers using Sun Cluster for auto failover.
# 4
I read deep in the QFS manual
The following restrictions apply to the Sun StorageTek QFS software in a Sun Cluster environment:
仭 The following restrictions apply to shared file systems:
- They can be configured only under the SUNW.qfs resource type. They cannot be configured under the HAStoragePlus resource type.
- They can be configured as scalable file systems used only by the Sun Cluster data service for Oracle Real Application Clusters.
I want to set up similar configuration with 2 servers, shared storage and failover. But the information above seems to rule this out. It looks like only Oracle RAC is supported as shared filesystem in Sun cluster environment.
Can anyone help me on this. I need the information urgently. Sun reps also said same thing to me! They tell me it's impossible to have active-active shared file system configuration. Only one host can have write access to the shared file system in Sun cluster environment!
# 5
I have found a lot more information after reading the Suncluster concepts document and the one about cluster filesystem
The Sun Architect in my part of the world seems to be completely confused about failover and scalable filesystem (and data services). The QFS file system is available only as scalable shared file system in Oracle. In a scalable filesystem it allows direct concurrent access from all nodes running Oracle Parallel server to all the disks (or raw files). This is because Oracle Parallel server needs direct access to a raw file/device. You can configure a raw file (whole partition) to be inserted into an Oracle tablespace. This is for high performance parallel data servers like Oracle, Sybase, IBM DB2, ...
A normal shared QFS file system does not allow this. You cannot have multiple instances of an application runnning on different nodes to open a file for writing at the same time with having the application being cluster aware. But you can have applications on different nodes opening different files at the same time. All access to files services must go through the master node. That's the only restriction. When this master node fails, we need to failover the cluster file system service to another node.
So my conclusion is that my Sun architect does not know what he was talking about when he says that only one node can have read/write access to the shared FQS file system. The other node(s) cannot have any access to the shared file system until after the failover.
Please confirm my reading of the information.
# 6
dmaivn,
To confirm your thoughts...
We have 4 webservers running iplanet, two "upload" servers ( FTP server, one not really doing anything ). NOTHING is clustered.
So we have two apps ( ftp, iplanet ) using a shared QFS disk. Iplanet needs to write to the doc root, which is located on the QFS share. Web page maintainer's, upload via FTP web pages.We also copy iplanet logs to the QFS share for pick-up from another system. While our web site isn't the biggest, it's pretty busy. Oh, and at night we have cron jobs running on the QFS share to correct file perms and clean up of "un-wanted" files.
So you don't need to be in a cluster to run a shared QFS disk for multiple systems.
HTH,
Tom de
# 7
Well, after I read a lot more, I came to the part where it talked about QFS under Sun Cluster environment. It really hit me when I read the restrictions. After all the wonderful about what QFS can do and what Sun cluster can do, it started to talk about what they cannot do together!
The QFS document then mentioned that for shared QFS, you can only run Oracle RAC. And for unshared QFS, you cannot make it a global filesystem in Sun Cluster environment. So the Sun architect was kind of right? But he did not admit that Sun cluster and QFS don';t really work together.
QFS looks useless under Sun cluster environment. You would be better off not having Sun cluster environment if you want to use QFS. But he denied that other products can do better. I found out that TruCluster 5.x can give you shared file system together with the AdvFs file system that can be shared. Non-cluster aware applications run fine as long as they don't overwrite each other's files. But this product would not run on Solaris.
The bit that I think the Sun presale dude missed is that you cannot use QFS, but you can use UFS instead. You can then export UFS filesystems as global filesystems. But the catch is that the I/O will travel via the interconnects of the servers rather than the highspeed FC connection between the multihosted storage system and the nodes. So the only node that is the master of the UFS filesystem get the highest speed access via the FC connection. The rest have to access the data via this master node. I suppose then you can have Sun cluster and failover feature.
So, my question remain. Is there a set of products that will allow Sun Sparc servers running Solaris to share multihosted storage at high speed and have failover feature as well? Something that works like TruCluster from on Digital Alpha platform running Digital Tru64 Unix. I am not sure if Veritas products will do the job. I will need to search wider out of Sun products. But we are stuck with Sun servers. Perhaps Sun just do not have things that will work for now.
# 8
HI:
Have you looked at HA/SAM (Just announced with SAM-QFS 4.6)
Still active/passive, but should do what you want. Ignore all the
Oracle RAC stuff. That is only if you are using Q-write with
RAC.
Since SC is a little heavy, we developed a quick and dirty failover
script for SAM-QFS metaserver when exported in a flat namespace NFS
environment. We would be glad to share. Let me know. We implemented it on this appliance: http://www.sun.com/servers/cr/contentinfrastructure/
and it seems to be working fine.
Email us back at cis-help@sun.com to get the development team covered.
Chris Wood
> Hi,
I hope this is the right place ( I looked
> around ). We have a Shared QFS installation.3
> 280r's, shareing/servering webdata. Everything has
> been running extermely well, untill today.
> The metadata server shutdown ( logs say button
> pressed ), without the metadata server up, the other
> two systems stopped being able to use the shared FS.
> This brings our web presence down. We have a
> loadbalancer in place for redunancy for the
> webservers , so its a little useless if there is
> still one point of failure.
So the
> question is can you have two ( or a standby )
> metadata servers running with QFS?
> />Thanks,
Tom de - still checking the docs
> at docs.sun.com
lcwjr at 2007-7-5 17:51:09 >
