-
sata raid
following up this thread;
https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=124&postid=857143
Got the SATA raid installed last night. 5 250 gig drives in a CI design tower with the Sonnet card, in our dual 2 G5. It’s an 8 bay tower so we can add more drives later if desired.
Striped using disk utility. Is there anyway to partition OS X raid volumes into multiple volumes? I couldn’t see any way to do that.
So far so good. Speed is great yielding more than 300 mb/s read and write (double the old Medea rt3) and our dropout problems seem to have gone away. Instalation was not bad but I had a hard time getting the cables to snap in positively. Is there something I don’t know about the connectors?
Good value, good performance. I’m impressed so far. Hoping it will go well from here.
Jason
-
10 Replies
-
you ask –
Striped using disk utility. Is there anyway to partition OS X raid volumes into multiple volumes? I couldn’t see any way to do that.REPLY – I am not aware of any way to use Apple Disk Utility to create partitions on a RAID 0 configuration. However, the easy way to do it is to purchase ATTO Express Stripe (www.attotech.com), which will easily allow you to partition your RAID 0 configuration.
I have asked Apple Tech support 2 different times how to do this, and I was put on “eternal hold” both times, after the Apple “techs” said “yea, I think it can be done”. Eternal hold to me means being put on hold for over 1 hour. At that point (twice), you get the impression that no one at Apple Tech support knows how to use Apple RAID Utility (I was asking about an Apple XServe RAID, which I no longer use, since all the SATA stuff has become stable).
Bob Zelin
-
Thanks Bob. I was wondering if It was just me but there doesn’t seem to be any way to do it. My theory is that multiple partitions are safer as losing one will not wipe out as much data. Do you agree that that would be the reason to partition?
Jason
-
If you loose a disk you loose all raid partions anyway – so that’s not a big help
-Kaspar
-
Kaspar is correct – unless you have a RAID 3 or RAID 5 (or RAID 50) system, the typical Apple/ATTO RAID 0 striping configuration will not help you, no matter how many partitions you set up. You can do RAID 1 (disk mirroring), but almost no one is willing to do that, becuase you lose 50% of your drive space (500 gigs becomes 250 gigs).
With that said, with the exception of the Apple XServe RAID (that uses Hitachi SATA drives), I have NEVER seen a SATA drive fail since I have started using them in April 2005. Now, less than a year is no great track record for long term performance, but SATA’s from Hitachi and Seagate have so far shown themselves to be pretty damn reliable. It is bizarre (and I don’t know why) that the only dead Hitachi SATA drives I have ever encountered have been from Apple XServe RAID systems, that “theoretically” have “hand picked” SATA drives by Apple.
Bob Zelin
-
Sometimes one can lose a volume.. the disks are all working but the directory has become so corrupt that it can’t be repaired.. in that case the other volumes would still be available.
At least that is the theory. But perhaps tools like disc warrier and data rescue can fix most of these problems. At least that is what I am hoping as right now we have only the one mega partition.
Jason
-
“Hand picked”.. interesting. As opposed to machine harvested.
j.
-
Hi Jason,
Thanks for letting us know about your new SATA disk array and those results sound great. It would also be very interesting to hear from you when the disk array is filling up to see if the disk array is still performing well. It will definitely slow down but the question will be by how much?
I just set up an 8 disk SATA II disk array with all drives striped as RAID 0. The speed was only around 148 MB/sec and it connected via a Fibre Channel card. I’m puzzled by the slow performance as it is too slow for HD. So you appear to have done very well 🙂
Regards,
Luke Maslen
Blackmagic Design -
Yes. Curious to see how much it slows down. Will let you know.
In the array you mention was it stripped using Apple Disc Utility or Atto express raid or some other?
Since we have the new drive we have solved a problem with a kind of “dropout” during playback but we noticed today that we still get a similar kind of dropout but only in rendered material. Puzzling. The solution is to make a cut and rerender just the frame with the dropout. A pain. I don’t believe that this is related to the drive.
started with an erased disc, Re installed OSX, reinstalled the application, reinstalled the decklink drivers etc…
Jason
-
Hi Jason,
Thank you for the extra details. That is weird but useful to know.
We always use Apple Disk Utility for striping as it does a good job and we know everyone has access to it whereas not everyone has the ATTO utilities. We use ATTO cards but still use the Apple Disk Utility for all testing and that is what we recommend to DeckLink customers.
Regards,
Luke Maslen
Blackmagic Design -
I just set up an 8 drive external sata array using an internal controller and I’m getting 340Mb/s with more like 500Mb/s sequential reads and writes in RAID 0, less in RAID 5 but I’m going to try a new PCIe controller. This is on a PC though (Supermicro H8DCE) and tested using Sandra, so I’m not sure how this compares to the throughput on a Mac. I’ve only done SD with it so far, but I’ll be testing HD with it all next week, I have a motion tracked HD virtual set to do. It would be really nice if that Multibridge Extreme I ordered 4 months ago would show up…
Eric Pratt
https://www.virtualsetworks.com
Reply to this Discussion! Login or Sign Up