StoreEasy Storage

Fastest Way to set This up??

Occasional Contributor

Fastest Way to set This up??

I am working on using an AiO1200 for an Exchange 2007 CCR server. As such, the Host an Exchange Storage Group option is not going to work (as evidenced in a previous thread). I am now setting this up using User-Defined Applications; which is working....kind of.

Problem 1:
When creating LUNs it fails 1/2 the time. It fails and says "drive is not yet initialized". I can then go in, initialize the drive, bring it online, and format it on the remote host....but unsure why I cannot get consistent response on the creation.

Problem 2:
This is more of a question than a problem. In creating these custom application LUNs, when the ASM has to add disks to the array and expand it, it takes a very long time. For example, setting up the initial 2 disk RAID 10 was seamless. We are at the point where 2 more disks (300GB) are being added. The expansion process is taking upwards of 7 hours to complete (with Expand Priority set at high). I am going to have to repeat this 3 more times for the subsequent disks being added.

Is it possible to create one large RAID 10 volume and then allow ASM to use it when setting up the custom applications? I attempted to to this, but when going through the Wizard it seems to only recognize unused disk space; and won't utilize the 1.4TB RAID 10 array.

End goal is going to be 1.4TB array with about 12 RAID 10 arrays for different storage group databases.

Thanks for any input.
Occasional Contributor

Re: Fastest Way to set This up??


End goal is going to be 1.4TB array with about 12 RAID 10 logical drives for different storage group databases
Jon Paul
Trusted Contributor

Re: Fastest Way to set This up??

Question 1: The error message you provided is incomplete (the event log has more complete information), so it is difficult to say exactly why you are experiencing this problem. However, ASM does rely on Microsoft's Virtual Disk Service (VDS) to Locate, Initialize and Format disks on Application servers. We have observed on some systems a tendency for VDS to provide inconsistent results. We are working with Microsoft to help resolve these issues.

Question 2: I am assuming that you are using the latest released version of ASM (1.3). In this version, ASM will automatically detect and display all storage that is provisioned manually by the user. ASM is also designed to make use of formatted storage when creating User Defined iSCSI storage for an Application Server - however, there are some caveats that you should be aware of:

a) ASM will not utilize Logical Disks (LUNs) that are not formatted into an NTFS Volume. ASM assumes that such storage has already been created for some other use.
b) ASM is designed to "grow" before "create". Thus, when you create one Logical Disk on an array, ASM will always try to "grow" that one instead of creating another Logical Disk.
c) ASM attempts to find best storage based on "Best Practice" algorithms". The customer has some control over which storage is selected, but this requires modifications in the "Advanced" dialog (in the storage sizing step in the wizard). This is not recommended practice, because getting the results you want is often hit and miss. There are also some provisioning scenarios which ASM simply will not do

Given that ASM is not designed to provide a custom storage layout, I would suggest the following:
1) Manually create an array or arrays (and hot spares) that consumes all the available disk drives.
2) Manually create all the Logical Disks that you want on the arrays - consuming all the space.
3) Manually format all the Logical Disks into NTFS volumes.

Once this is done, then ASM will utilize this storage when creating iSCSI LUNs for the Application Server. It is important to consume all the available storage so that ASM doesn't attempt to choose unallocated storage, or grow the existing storage. Finally, keep in mind that if ASM can find enough storage on a Volume to place an iSCSI LUN, it will do so, even if there are already other iSCSI LUNs being hosted there. This will be important when you try to distribute the iSCSI LUNs among all your volumes.

By the way, expanding an existing array to include more disks will always take a long time. This is because the data has to be completely restriped across all the disks again. It is not uncommon for a restriping to take 7 hours or more.