Paging Bob ‘SATA’ Zelin…

[Kevin Hedin]

Bob, can’t you also use RAID 1 (mirror) for simultaneous backup? I haven’t tried this before, but I’m assuming that you can separate the drives afterward, and put one on the shelf for backup and start using the other drive to edit with. Has anyone tried this?

[Ed Dooley]

Yes, sort of. I don’t think the built-in Disk Utility will allow you to do a RAID1, and performance
on the important Write part of throughput is less than a single drive, so you’ll take a performance hit.
Ed

This is from IBM:
>>>RAID 1 is also known as disk mirroring. It is most suited to applications that require high data availability, good read response times, and where cost is a secondary issue. The response time for writes can be somewhat slower than for a single disk, depending on the write policy; the writes can either be executed in parallel for speed or serially for safety. Select RAID Level 1 for applications with a high percentage of read operations and where the cost is not the major concern.<<< Ken Stone offers this advice about RAID1 (https://www.kenstone.net/fcp_homepage/raids_defined_golden.html): >>>RAID 1 – If you want some level of redundancy but cannot afford Raid 5 then go with Raid 1(mirroring) you do not gain any speed but you do have the advantage of having an instant 2nd copy of your files. But if you are NOT using some form of backup that works for your environment then this might be a waste. Since, if you write bad data out, it is bad in 2 places instantaneously AND in the very small possibility that the controller goes bad you will write garbage to both drives thus rendering them both useless… Again lots of vendors offer this solution.<<< Another tech site: >>>RAID-1
RAID Level 1 provides redundancy by writing all data to two or more drives. The performance of a level 1 array tends to be faster on reads and slower on writes compared to a single drive, but if either drive fails, no data is lost. This is a good entry-level redundant system, since only two drives are required; however, since one drive is used to store a duplicate of the data, the cost per megabyte is high. This level is commonly referred to as mirroring.<<< This from PCStats, a test of an Adaptec controller with RAID1 (it basically says the same as above): https://www.pcstats.com/articleview.cfm?articleid=616&page=7

[Kevin Hedin] “Bob, can’t you also use RAID 1 (mirror) for simultaneous backup? I haven’t tried this before, but I’m assuming that you can separate the drives afterward, and put one on the shelf for backup and start using the other drive to edit with. Has anyone tried this?”

[Bob Zelin]

My God, this thread is never going to end !!!!!

I hate Apple’s software RAID 1 solution. Here is why –

1) with a 2 drive SATA RAID 1, you lose half of your disk performance. Using AJA Kona System Test, a 128mb/sec RAID 0 array, goes down to about 68mb/sec at RAID 1. Which means that you aint’ doing 10 bit uncompressed SDI with a RAID 1.

AND the REAL reason I hate RAID 1 with Apple –

2) I don’t always get to use Firmtek SATA host cards, and sometimes I have to use the Sonnet Tempo X 8 port. You have heard me bitch about these in the past, becuase of their poor eSATA connectors. (The E4P seems better). Anyway, if you use the Sonnet 8 port, and do a RAID 1, and someone goes behind the computer to plug in a FW drive, and brushes to firmly on the eSATA cables, it will temporary “disconnect” the RAID drive array, making the Apple think that the RAID has failed (even if it is only for a brief moment). Then, Apple Disk Utility reports RAID FAILED. They you have to go back in and retore the RAID, which TAKES 24 HOURS on two lousy 500 gig drives. And of course, there is nothing wrong with the drives, just one got disconnected for a second. I have found that it is easier to dump your material off on FW800 drive from the RAID 1, delete and recreate the raid 1, and then drag the media back onto the SATA RAID drives. The process takes a few hours, not 24 hours.

SO NO, I am not a big Apple RAID 1 fan.

Bob Zelin

[Jeremy Garchow]

[Bob Zelin] “My God, this thread is never going to end !!!!!”

Got that right. Received all of my stuff. The enclosure seems awesome. Got it from Maxx Digital and they are great guys over there. The card I got from Granite Digital. Everything works, but I am a little disappointed. Raid 1 performance is deplorable 15 MB second. Not a big deal as I was going to use this for HVX200 transfers for auto backup purposes. The biggest disappointment is a stripe. I am only getting 30 MB sec. This sucks. The single drives get over 60 MB second on there own when they are both mounted. This performance is fine for my needs for this upcoming gig, but I was hoping I could step it up a notch in the future. I’d be wary of doing anything uncompressed with this setup. it was my goal and I am now thinking I should have stuck with the tired and true FW 800. Maybe the firmtek card will prove faster performance, but somehow I doubt it. Oh well. SATA technology bites me in the ass again. When can I hook up my Huge RAID to my powerbook? At least this setup will work, it just doesn’t work like I had hoped.

Jeremy