Xserve RAID Striping Examples


There are numerous ways to stripe your available Xserve RAID units, depending on the number of RAIDs, as well as your bandwidth need, requirements for audio and render space, as well as other factors such as AFP/NFS/SMB file sharing LUNs.

The following sections present a few examples of how you may divide up your available RAIDs for use with Xsan. Because this will be one of the more creative tasks in the Xsan configuration, we will coin this term LUNscaping.

In all implementations of Xsan, it is highly recommended that you create a separate metadata and journaling pool that resides on its own controller of your Xserve RAID. This will allow the controller to be optimized for dealing with these small metadata files and give you the best possible bandwidth out of your SAN. If you are not able to dedicate one controller for this task, then it is possible to share the metadata and journaling controller with other data pools. Realize, however, that if you decide to mix the metadata and journaling information with regular data, you will not be able to expand the volume in the future.

One Xserve RAID

Option 1

This configuration assumes that the media pool contains both metadata and journaling, as well as user data. This method can be used when you need to get the greatest bandwidth from your small SAN, and the number of users is minimal.

This configuration will yield approximately 160 to 200 MB/s and can be used for DV and SD capture and playback.

Option 2

In this setup, we have created a LUN specifically for metadata and journaling information. If assigned properly in Xsan Admin, this pool will not be able to be used for any other type of media. It has been created as a RAID level 1, which means that either drive could fail, and the other drive would take over its duties.

The media pool comprises two LUNs, each RAID 5. This configuration will still yield approximately 160 to 200 MB/s bandwidth, so it is suitable for DV and SD recording and playback.

There is also an additional render pool composed of a two-drive RAID 0. Although we recommend placing render media on local hard drives, this is a viable alternative if the render media must reside on the SAN. It is striped as RAID 0 for speed, which means we have no redundancy in case of a drive malfunction. This is not an issue, however, since render files can easily be recreated in case of a drive failure.

Two Xserve RAIDs

Option 1

When configuring two or more RAIDs, it is optimal to have a separate metadata and journaling pool. The render pool has been striped as RAID level 5 for redundancy, and the audio pool is striped as a mirrored RAID level 1. The rest of the drives are all incorporated in one large video pool and should yield approximately 240 to 300 MB/s throughput.

This configuration is suitable for multiple users recording and playing back DV, SD, and HD material.

Option 2

Similar to option 1, this configuration could be utilized when the bandwidth need is not as great, and the quantity of render files will be much more substantial.

We have also increased our capacity for audio files because its pool has increased in size as well.

This configuration will yield approximately 160 to 200 MB/s when writing to the video pool, and it is optimized for DV and SD material.

Three Xserve RAIDs

Option 1

Identical to the previous example, this option simply adds another Xserve RAID to our video pool. This addition increases our available bandwidth by 160 MB/s, giving us a total of 320 to 400 MB/s from our video pool.

Option 2

This configuration takes into account that for optimum performance, the metadata and journaling pool should occupy its own controller. Notice that we have placed one hot spare in case of a drive failure, but left the remaining drive slots empty in the first controller. This configuration will yield approximately 400 to 500 MB/s when writing to the video pool, and is optimized for DV, SD, and some HD material.

Four Xserve RAIDs

Option 1

Option 2



Apple Pro Training Series. Xsan Quick-Reference Guide
Apple Pro Training Series: Xsan Quick-Reference Guide (2nd Edition)
ISBN: 0321432320
EAN: 2147483647
Year: 2004
Pages: 120

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