Rorke Galaxy HDX vs. Xserve/Xraid with 4 FCP stations

[Bernard Lamborelle]

Hi John,

We tested the Galaxy HDX when I was with Matrox. We were able to obtain 335MB/sec of effective throughput. It is possible that Rorke was able to improve their performance slightly. While I haven’t seen the Galaxy operate with DV50 streams, a little math will help:

One DV50 stream = 50Mbps or 6.25MB/sec

This means that *in theory* you can fit over 50x DV50 streams. I say “in theory” because concurrent accesses with different streams will force lots of seeking on the drives, that will affect the overall performance. This is one area where SATA drives can have an effect. I don’t know about SATA II but regular SATA are not as good for concurrent accesses as SCSI drives.

You are probably safe to assume you can get 25x streams out of this box. Can you get 30 or 40? Maybe but I really don’t know. Perhaps someone else has hands on experience and can tell us.

With regards to Xserve, the practical bandwitdh should be very close. The question of defragmenting, etc. will be the same on both storage unit as this is more a question of the file system, the application you use, and the administrative tools you use.

Outside of performance, the main characteristics to look for in a storage unit is the type of RAID configuration (for data security); hot swappable drives or not; redundant power supplly; reliability; support; and price of course!

In theory, you should never have to reformat a drive once it has been formatted. The only reason to re-format would be because the drive got corrupted (shouldn’t happen) or you need to re-stripe the drives in a new configuration (to increase your network bandwidth for instance).

Finally, you should consider that many SAN management software come with their own, proprietary file system (such as Xsan and Sanergy). This means that once you have formatted the drive with this foreign file system, you can’t attach your storage to a regular computer anymore, without having to either load the SAN management software onto it (costs you a lincense) or re-format the drive (and lose all your data!). Other SAN management software, such as MetaSAN and FibreJet utilizes native HFS+ file systems, so you never have to do this.

Hope this helps.

Bernard

[John]

Bernard

Thanks for your response. The Rorke Galaxy does use fibreJet meaing the drives will be formatted HFS+.

After talking to some people who are currently using the Galaxy I am pretty sure I will be going this route. Once I get the system up an running I will post my finding for all in this forum.

Thanks
John

[Shane Chadder]

Does the Rorke allow for file sharing between multiple stations or do you need a server for that?

[Bernard Lamborelle]

Shane,

The Galaxy HDX is a Fibre Channel storage. File sharing therefore requires one or more server.

Depending on the type of material, and the number of streams you need to feed (i.e. DV, DV50, uncompressed, etc.) you might be able to get away with a simple server feeding Gigabit Ethernet LAN clients, or you might need to invest in a more complex Fibre Channel SAN with each client having access to the storage through a Fibre Channel switch…

When you try to access or edit multiple DV video streams over a regular Gigabit Ethernet network, you will find out that you quickly get drop frames. That is because the network file protocol is not very good at streaming. For this reason, many people purchase specialized storage units that can be very expensive.

Tiger Technology makes a unique software that streamlines workgroup collaboration over Gigabit Ethernet by:

– increasing network performance by transfering data using block access instead file protocols
– allocating network bandwidth to each client to ensure smooth playback
– allows Windows, Mac, and Linux clients to share the same files
– ensures network scalability and 24/7 failover capabilities for mission critical environments

But if you need it, the same software functionality, and more is available for Fibre Channel or iSCSI SAN as well.

Cheers,

Bernard Lamborelle
http://www.tiger-technology.com

[John]

Bernard,

“The Galaxy HDX is a Fibre Channel storage. File sharing therefore requires one or more server.”

Actually with the FibreJet software you don’t need a server involved. Drives are stripped HFS+ and show up through the fibre channel HBA just like any other direct attached storage. After making your partitions you then use the FibreJet software to assign read/write access to indivual clients(computers) that are attached to the fibre switch. Having no servers involved is one reason I really like this solution.

John

[Bernard Lamborelle]

John,

The point you are making is that FibreJet

[Olivier Jean]

HI,

that’s spot on.
This is one of a good thing of FibreJet.
And Couldn’t be easier to set up ;-).

Regards
Olivier Jean
Powermedia Systems
Sydney Australia