You can only share disk space between Windows servers if you turn them into a Microsoft Cluster.
Remove access to the disks for 1 server and you'll be fine.
When using block level storage (like a SAN (whether it's fibre channel, iscsi or sas)), servers can only share disk space if there's some software in place that regulates which server gets to access which resource (virtual disk) at which time.
If you don't have any such software in place, you'll corrupt the filesystem and it's expected to run into data corruption/loss and other issues (like needing to run checkdisk on every boot).
oh, noted. Am really appreciate it and really thanks alot
Again, if the storage and both server configure into cluster mode and the issue will be resolve? i'm not sure how the other SQL team will configure the cluster anyway, maybe you can help me with furture info with the cluster setting like refference or link?
In a (Microsoft) cluster, the cluster service only allows 1 node (server) at a time to access any given disk, so that IO to that disk is safe.
If 2 servers share a disk without software in place to manage this, the following situation can/will happen; one server starts writing to the disk, as it doesn't know about the other server it assumes it's the sole owner of the disk and can write to it as it pleases. Now the other server 'decides' to write to the disk as well. It doesn't have to 're-poll' what the latest state of the disk is (which data is where), as it's the only server using the disk in it's mind. So what happens is that this 2nd server can/will end up overwriting the data that the first server just wrote to the disk. This means you just lost the data that the first server wrote.
To set up a Microsoft cluster, there are a few requirements:
- all nodes that'll be in the cluster need to be in the same domain
- all nodes need a static IP address (I think you can force DHCP, but clustering really doesn't like this, even if you use reservations on your DHCP server)
- all nodes need to be running Windows 2000 Advanced Server, Windows 2003 Enterprise Edition, or Windows 2008 Enterprise Edition (or a Data Center version of these versions). NOTE: the MD3000 isn't certified for Windows 2000 clustering, but these OSes are for 'general clustering requirements'.
- the servers need to be running the same architecture (all 32-bit, or all x64; no mixes)
- highly recommended is to have a NIC in each server that can be dedicated to a heartbeat (private link between the servers). If it'll just be a 2-node cluster, this can be a patch/crossover cable. This will need a unique subnet (different from your regular network) with static IP addresses.
- You'll need a Quorum disk on the shared storage solution. This can be a regular data-disk, but as the quorum disk has certain limitations (e.g. if I'm not mistaken volume shadow copy cannot be done on the Quorum disk), it's recommended to just make a 1GB virtual disk on the MD3000 and reserve this for the Quorum (most people assign it drive letter Q, but this isn't a requirement).
A few notes about clustering:
- only 1 server can access a disk at a time
- if you want all (cluster) servers to be 'doing' something, you'll need to make multiple virtual disks and in the cluster create multiple cluster groups; each group will have it's own disk (if needed), own IP (if needed), and own DNS name (if needed).
Dev Mgr
4 Operator
•
9.3K Posts
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September 10th, 2008 16:00
Remove access to the disks for 1 server and you'll be fine.
When using block level storage (like a SAN (whether it's fibre channel, iscsi or sas)), servers can only share disk space if there's some software in place that regulates which server gets to access which resource (virtual disk) at which time.
If you don't have any such software in place, you'll corrupt the filesystem and it's expected to run into data corruption/loss and other issues (like needing to run checkdisk on every boot).
yw_sau
3 Posts
0
September 11th, 2008 11:00
oh, noted. Am really appreciate it and really thanks alot
Again, if the storage and both server configure into cluster mode and the issue will be resolve? i'm not sure how the other SQL team will configure the cluster anyway, maybe you can help me with furture info with the cluster setting like refference or link?
Dev Mgr
4 Operator
•
9.3K Posts
0
September 11th, 2008 12:00
If 2 servers share a disk without software in place to manage this, the following situation can/will happen; one server starts writing to the disk, as it doesn't know about the other server it assumes it's the sole owner of the disk and can write to it as it pleases. Now the other server 'decides' to write to the disk as well. It doesn't have to 're-poll' what the latest state of the disk is (which data is where), as it's the only server using the disk in it's mind. So what happens is that this 2nd server can/will end up overwriting the data that the first server just wrote to the disk. This means you just lost the data that the first server wrote.
To set up a Microsoft cluster, there are a few requirements:
- all nodes that'll be in the cluster need to be in the same domain
- all nodes need a static IP address (I think you can force DHCP, but clustering really doesn't like this, even if you use reservations on your DHCP server)
- all nodes need to be running Windows 2000 Advanced Server, Windows 2003 Enterprise Edition, or Windows 2008 Enterprise Edition (or a Data Center version of these versions). NOTE: the MD3000 isn't certified for Windows 2000 clustering, but these OSes are for 'general clustering requirements'.
- the servers need to be running the same architecture (all 32-bit, or all x64; no mixes)
- highly recommended is to have a NIC in each server that can be dedicated to a heartbeat (private link between the servers). If it'll just be a 2-node cluster, this can be a patch/crossover cable. This will need a unique subnet (different from your regular network) with static IP addresses.
- You'll need a Quorum disk on the shared storage solution. This can be a regular data-disk, but as the quorum disk has certain limitations (e.g. if I'm not mistaken volume shadow copy cannot be done on the Quorum disk), it's recommended to just make a 1GB virtual disk on the MD3000 and reserve this for the Quorum (most people assign it drive letter Q, but this isn't a requirement).
A few notes about clustering:
- only 1 server can access a disk at a time
- if you want all (cluster) servers to be 'doing' something, you'll need to make multiple virtual disks and in the cluster create multiple cluster groups; each group will have it's own disk (if needed), own IP (if needed), and own DNS name (if needed).
yw_sau
3 Posts
0
September 12th, 2008 13:00
okie, noted and thanks for the reply
really appreaciate it :)