To detect issues within the hard drive you will want to run the Patrol Read. The Patrol Read checks for physical disk errors that could lead to drive failure, where as the consistency check is the process by which it checks for and corrects inconsistencies between a volume and its mirror.
If you have bad blocks on the drive it can explain the drive performing slower, as the controller has to write around those blocks.
Check if all the firmware's are the same on the drives in the affected array. Also speed could be affected by how much data is on the affected array, as compared to the other arrays. You should have Patrol reads in the automatic mode or set off as a task, never disabled, definitely run it as suggested.
Run chkdsk, run the Dell Diags, indexing off?
what is "way slower? 5,10 15. 20, 30, 40% How are you testing ?
We use 'iostat -x 10', and looked at the await and svctm closely. Comparing with sdb (vdisk1), sdc (vdisk2), sdd (vdisk3), the sde (vdisk4), has a much higher delay (see await and svctm) while provides fewer throughputs (rsec/s).
The rebuild finished successfully after replacing the HD. Since then the vdisk has performed on par with other vdisks. Most likely we got lucky by replacing the bad physical disk.
We will set up monthly patrol read as recommended.
DELL-Chris H
Moderator
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9.7K Posts
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September 18th, 2013 13:00
WilsonH,
To detect issues within the hard drive you will want to run the Patrol Read. The Patrol Read checks for physical disk errors that could lead to drive failure, where as the consistency check is the process by which it checks for and corrects inconsistencies between a volume and its mirror.
If you have bad blocks on the drive it can explain the drive performing slower, as the controller has to write around those blocks.
Let me know if this helps.
pcmeiners
4 Operator
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1.8K Posts
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September 18th, 2013 15:00
Check if all the firmware's are the same on the drives in the affected array. Also speed could be affected by how much data is on the affected array, as compared to the other arrays. You should have Patrol reads in the automatic mode or set off as a task, never disabled, definitely run it as suggested.
Run chkdsk, run the Dell Diags, indexing off?
what is "way slower? 5,10 15. 20, 30, 40% How are you testing ?
wilsonh
4 Posts
0
September 18th, 2013 16:00
We have decided to replace a pdisk which has not been replaced recently, and started a RAID rebuild. Will see how it goes.
wilsonh
4 Posts
0
September 18th, 2013 16:00
We use 'iostat -x 10', and looked at the await and svctm closely. Comparing with sdb (vdisk1), sdc (vdisk2), sdd (vdisk3), the sde (vdisk4), has a much higher delay (see await and svctm) while provides fewer throughputs (rsec/s).
Example 1: mostly read op on all vdisks:
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.80 0.10 0.60 2.40 11.20 19.43 0.00 0.86 0.86 0.06
sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sda2 0.00 0.20 0.00 0.20 0.00 3.20 16.00 0.00 3.00 3.00 0.06
sda3 0.00 0.60 0.10 0.40 2.40 8.00 20.80 0.00 0.00 0.00 0.00
sdb 860.10 4.50 1058.20 1.90 258236.80 51.20 243.64 3.91 3.69 0.94 100.00
sdb1 488.80 2.40 605.70 0.90 148018.40 26.40 244.06 1.94 3.22 1.62 98.02
sdb2 371.30 2.10 452.50 1.00 110218.40 24.80 243.09 1.97 4.31 2.18 98.67
sdc 1067.50 4.00 1311.30 2.10 320044.80 48.80 243.71 3.90 2.97 0.76 100.00
sdc1 543.70 1.60 668.20 1.00 163010.40 20.80 243.62 2.00 2.99 1.46 97.80
sdc2 523.80 2.40 643.10 1.10 157034.40 28.00 243.81 1.90 2.94 1.52 98.03
sdd 1033.90 3.30 1258.40 2.00 307668.00 42.40 244.14 3.97 3.15 0.79 100.00
sdd1 469.50 1.70 576.00 1.00 140537.60 21.60 243.60 2.06 3.56 1.70 98.17
sdd2 564.40 1.60 682.40 1.00 167130.40 20.80 244.59 1.92 2.79 1.43 98.03
sde 289.90 3.30 356.70 1.90 86857.60 41.60 242.33 4.19 11.71 2.79 100.01
sde1 51.10 1.70 66.60 0.90 15948.80 20.80 236.59 2.16 31.96 14.78 99.79
sde2 238.80 1.60 290.10 1.00 70908.80 20.80 243.66 2.03 7.01 3.42 99.53
Example 2: mostly read op on vdisk4 (sde)
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 2.20 1.40 0.60 11.20 22.40 16.80 0.01 4.60 4.60 0.92
sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sda2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sda3 0.00 2.20 1.40 0.60 11.20 22.40 16.80 0.01 4.60 4.60 0.92
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdc1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdc2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdd1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdd2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sde 129.60 0.20 186.60 0.40 40115.20 4.80 214.55 6.29 33.34 5.35 100.02
sde1 120.60 0.00 151.00 0.00 36694.40 0.00 243.01 1.95 12.89 6.62 100.02
sde2 9.00 0.20 35.60 0.40 3420.80 4.80 95.16 4.35 119.13 27.77 99.98
wilsonh
4 Posts
0
September 24th, 2013 15:00
The rebuild finished successfully after replacing the HD. Since then the vdisk has performed on par with other vdisks. Most likely we got lucky by replacing the bad physical disk.
We will set up monthly patrol read as recommended.
Thank you.