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Old 10-12-1999, 07:07 PM
hrob hrob is offline
Join Date: Oct 1999
Location: Newton MA USA
Posts: 80
Default Duplexed Disks with Pro Tools

I do live recording with Pro Tools which generates a huge amount of data (easily 35G in one day). This makes me more sensitive to the problem we all deal with: Managining and backing up huge amounts of data. From a management standpoint, I have gone with Dataport VI SCA sleds so I can swap hard drives (I've been waiting for usable removable media to come along for a while, now, but I eventually gave up). The Anubis disk driver handles the Dataport Sleds (with a certain amount of rough edges if they aren't up to speed when the machine boots).

That handles the management aspect (although, not cheaply). The remaining problem is backup. All tape is unreliable; therefore, you have to make 2 or 3 backups to be safe. Tape is also too slow. With an Eliant 820, it takes 12 hours to make ONE copy of a 35G session (which took 5 hours to record). Two copies is 24 hours. With a Mamouth that would drop to 8 hours and with a DLT-70, that would drop to about 5 hours. Those options are still too slow and the media cost for them skyrockets because they are non-standard.

The solution to this problem is to use two disks with duplicate data. This technique is called "Disk Duplexing" or "Raid 1"

I have been experimenting with disk duplexing and PT and have found a compatibility problem with Remus Lite and Connor Softraid. In both cases, they work with a 1G partition, but fail immediately with a -9060 error when I try to record on a 16G partition. The failure is very immediate and happens with only one track; so, it's pretty clearly not a performance issue. This works with Anubis Raid and FWB Raid; so, I assume this is some function that the other two haven't implemented. Can anyone out there tell me what that function is so I can report the problem to Adaptec and Connor?

Note: I tried increasing the DAE buffers to the max and tried recording onto just one track (I started out recording to all 32 tracks, which works with Anubis and FWB --they are very close to the disk speed limit with all 32 tracks on one 18G Barricuda, but they do work).

Preliminary Report on My Test Results:

The Anubis and FWB Raid drivers do work with PT and they don't have any noticable effect on the PCI utilization that PT meters. They are also pretty rinky dink in other aspects... Nobody's driver even came close to passing my tests. Anubis breaks the duplexing if you boot once with one of the disks powered down and the other powered up. FWB has no way to mount the disks if they aren't both up when the machine boots. Didn't test the case where only one drive is powered up (yet). Both FWB and Anubis failed to recover from a simulated disk error (switching off the power) -- in fact, they hung PT to the point where I couldn't even force quit: As you would expect, the recorded contents was unusable on both disks because of the reboot. I didn't perform this test with Remus Lite and Connor because they had failed previous testing.

Testing was done with a Beige G3/266 with a Bit3 Seven Slot chassis and an Adaptec 3940UW. The PT system consists of a d24 and two classic farms. There were no other PCI cards in the system. The duplexed disks were split across the two SCSI busses from the 3940.

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Old 10-13-1999, 09:26 PM
hrob hrob is offline
Join Date: Oct 1999
Location: Newton MA USA
Posts: 80
Default Re: Duplexed Disks with Pro Tools

I should have posted this under "Storage Subsystem Issues. I'm going to report there. Please continue the thread there....
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