meep Posted February 5, 2011 Share Posted February 5, 2011 So, I'm setting up a quick n dirty unRaid to play with Beta 5. Wondering with all drives newly formatted, why I need to sit through a full parity sync. Is there any option that essentially says 'all my drives are newly formatted, just write zeros to the parity drive (and do it quickly!) ' Maybe I misunderstand what's going on but it seems a bit of a waste to site around hours several hors for unRaid to figure out all the drives are empty when I could just tell it. Maybe there's some bad sector voodoo going on? Peter Link to comment
SSD Posted February 5, 2011 Share Posted February 5, 2011 So, I'm setting up a quick n dirty unRaid to play with Beta 5. Wondering with all drives newly formatted, why I need to sit through a full parity sync. Is there any option that essentially says 'all my drives are newly formatted, just write zeros to the parity drive (and do it quickly!) ' Maybe I misunderstand what's going on but it seems a bit of a waste to site around hours several hors for unRaid to figure out all the drives are empty when I could just tell it. Maybe there's some bad sector voodoo going on? Peter Did you preclear all of your disks, including parity, before creating your array. Newly formatted is useless. I will confess I have never created a new array with all precleared disks, so not sure if it is optimized to not compute parity at all in these cases. But it is possible that it is. What is the parity build speed you are seeing? Final comment - writing 0s to a 2T disk, even at a very respectable 100 MB/sec, will take between 5.5 and 6 hours. So quickly in this context is not exactly instant! Link to comment
meep Posted February 5, 2011 Author Share Posted February 5, 2011 Have not run preclear Seeing 51 MB/s on parity sync and have an est. 6 hours to do 1x 1TB Parity & 3x 1TB Drives. Maybe this is as good as it gets. Was just thinking there might be a possibility of a shortcut :-( Peter Link to comment
Benni-chan Posted February 5, 2011 Share Posted February 5, 2011 i used two precleared 2TB drives to create a new array some days ago. unraid did perform the initial parity check (which took about 6 hours). so the preclear brings no speed up on the initial array creation. Link to comment
SSD Posted February 5, 2011 Share Posted February 5, 2011 Have not run preclear Seeing 51 MB/s on parity sync and have an est. 6 hours to do 1x 1TB Parity & 3x 1TB Drives. Maybe this is as good as it gets. Was just thinking there might be a possibility of a shortcut :-( Peter 51 MB/sec is quite good for parity build. unRAID teaches you a certain amount of patience. Link to comment
dgaschk Posted February 6, 2011 Share Posted February 6, 2011 unRaid computes parity across the bits in each data disks partition. The drives are not exactly empty. There is file system formatting and different sized disks will have bits in different places even when empty. Link to comment
dwoods99 Posted February 6, 2011 Share Posted February 6, 2011 For comparison, I just finished building 10 drives, 7x 2TB & 3x 1TB (including 2TB parity drive). Using 4.7, I pre-cleared all drives (30+ hours for each 2TB drive). Filled data up to 3/4 full, and assigned parity drive. Started array to start parity sync (first time), and I expected that 15TB would take 3-4 days... It was done in 30 hours with 0 errors. Link to comment
Joe L. Posted February 6, 2011 Share Posted February 6, 2011 For comparison, I just finished building 10 drives, 7x 2TB & 3x 1TB (including 2TB parity drive). Using 4.7, I pre-cleared all drives (30+ hours for each 2TB drive). Filled data up to 3/4 full, and assigned parity drive. Started array to start parity sync (first time), and I expected that 15TB would take 3-4 days... It was done in 30 hours with 0 errors. There were no read errors on the data disks, and no write errors from the parity disk, but you will not know if what you have written to the parity disk is readable until you perform a subsequent parity check. You should press the "check" button now. If it finishes with zero parity sync errors, then you are truly protected. Link to comment
dwoods99 Posted February 6, 2011 Share Posted February 6, 2011 'Check'ing parity sync again... Total size: 1,953,514,552 KB Current position: 2,290,528 (0.1%) Estimated speed: 15,701 KB/sec Estimated finish: 2070.9 minutes Sync errors: 0 Link to comment
bcbgboy13 Posted February 7, 2011 Share Posted February 7, 2011 Filled data up to 3/4 full, and assigned parity drive. Started array to start parity sync (first time), and I expected that 15TB would take 3-4 days... It was done in 30 hours with 0 errors. 30 hours is very "slow speed" - my guess is you are using 6 onboard SATA slot plus a cheap 4-port PCI SATA card for this 10-drive system. And perhaps ever worse with multiple PCI based controllers. Attach the three 1TB drives to the SATA card - in this way you will improve your speed a bit as once the 1TB mark is done you will have a single drive to the PCI bus and this is very acceptable. Link to comment
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