February 23, 201313 yr I have the following disks in my server: Data disks: SAMSUNG_HD103UJ 3x 7200 SAMSUNG_HD204UI 1x 5400 WDC_WD20EARS 4x 5400/5900 Hitachi_HDS723030ALA640 4x 7200 Hitachi_HDS722020ALA330 1x 7200 Hitachi_HUA722020ALA331 2x 7200 Parity 3 TB RAID0 volume on ARC 1200 Cache 500 GB RAID1 volume on ARC 1200 What should be, on average, the obtainable Parity Build speed of this array? The parity rebuild finished this morning with the following: Feb 23 11:06:17 Tower1 kernel: md: sync done. time=43682sec (unRAID engine) 12 hours for 3 TB? Is this time about right?
February 23, 201313 yr You may want to play with the disk tunables to improve performance... My configuration with 3TB takes about 10 hours.
February 25, 201313 yr Author You may want to play with the disk tunables to improve performance... My configuration with 3TB takes about 10 hours. over How far can I go with those tunables? Sounds pretty tricky to me. Data integrity is more important to me than the highest speeds possible. Besides I thinks that 3 different disk-sizes does influence parity sync an parity check speed too. Parity sync and check now start a 90 MB/s slowly dropping to 60 MB/s at the 1 TB over 1 TB it climbs to 85 dropping to 55 at 2 TB over 2 TB it climbs to over 100 MB/s dropping to 60 towards 3 TB. If all disks in the array were 3 TB 7200 rpm disks I also would get higher speeds I think.
February 25, 201313 yr You may want to play with the disk tunables to improve performance... My configuration with 3TB takes about 10 hours. over How far can I go with those tunables? Sounds pretty tricky to me. Data integrity is more important to me than the highest speeds possible. Besides I thinks that 3 different disk-sizes does influence parity sync an parity check speed too. Parity sync and check now start a 90 MB/s slowly dropping to 60 MB/s at the 1 TB over 1 TB it climbs to 85 dropping to 55 at 2 TB over 2 TB it climbs to over 100 MB/s dropping to 60 towards 3 TB. If all disks in the array were 3 TB 7200 rpm disks I also would get higher speeds I think. Your speeds are completely normal. Remember, for ANY disk the access speed on inner cylinders is far slower than on the outer cylinders. When you have different size disks, you'll be limited by the speed of the slowest disk at any time. You'll see slowdowns when you near the 1TB, 2TB, and 3TB ranges.
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