PERC 5/i RAID Card: Tips and Benchmarks - Page 158 - Overclock.net

DJZeratul · 03-15-09

Quote:

Originally Posted by iakovl

people,
what is patrol read and how should i set it

Patrol Read is a feature for identifying disk errors in order to avoid disk failures and data loss or corruption. The Patrol Read only runs on disks that are being used in a virtual disk or that are hot spares.

When possible, the Patrol Read corrects disk errors and restores the integrity of the data. The Patrol Read task runs in the background. When the Patrol Read mode is set to Auto, the Patrol Read is initiated when the controller has been idle for a period of time and when no other background tasks are active. In this circumstance, the Patrol Read feature also enhances system performance as disk errors can be identified and corrected while the disk is not the subject of I/O activity.

The controller adjusts the amount of system resources dedicated to the Patrol Read based on the amount of controller activity that is competing with the Patrol Read task. During heavy controller activity, fewer system resources are dedicated to the Patrol Read task.

The Patrol Read will not run on a physical disk in the following circumstances:

The physical disk is not included in a virtual disk or assigned as a hot spare.
The physical disk is included in a virtual disk that is currently undergoing one of the following:
- A rebuild
- A reconfiguration or reconstruction
- A background initialization
- A check consistency

In addition, the Patrol Read suspends during heavy I/O activity and resumes when the I/O is finished.

Hence, I would leave it set to auto. Unless you have a ton of stuff going on on your drive and you dont want to impact performance (server environment).

SockMan! · 03-16-09

A quick google search for "patrol read raid" and I found this:

http://www.dell.com/downloads/global...0212-Habas.pdf

Basically speaking, they're features that will help reduce the chances of losing data should an array fall into a degraded state. Of course, it only applies to real RAID arrays (not RAID0 or individual disks; neither of which have redundancy or parity).

I personally set patrol read to continuous for all my controllers since I don't care as much about performance as data integrity. I don't know what I'll do yet about consistency checks; I think I'll set mine on a weekly schedule.

{core2duo}werd · 03-16-09

well, i added a fourth drive, but now there are some weird dips in my benchmarks. i had more, but they went away when i defragged. the HD tach 100% CPU usage is because i am folding.

Edit: i ran the windows defrag, and it fixed it.

uberjon · 03-16-09

a comparison of raid5 vs raid0.. i just reconstructed my array to raid0

(sweeeeeeet feature!)

raid5 128k stripe 128k block size, slowest (accurate) setting

raid0 same settings "i think" only change was the 512MB dimm vs 256..

little rocky, i think i may try a defrag or two..

note: both are tested on my 4x SAS 15k 3.5 maxtor drives 36GB

i will say, either im totally nutts.. or i "did" notice the change when i rebooted.. from logon to firefox opening took about 35% less time!

utnorris · 03-16-09

A couple quick questions:

1 - Will a raid configuration from a ICH10R migrate to the Perc 5i or will I need to clone/rebuild it?
2 - Am I correct that on a X58 board this should just pop in and and be good to go or is the tape mod still needed?

Thanks

DJZeratul · 03-16-09

Quote:

Originally Posted by utnorris

A couple quick questions:

1 - Will a raid configuration from a ICH10R migrate to the Perc 5i or will I need to clone/rebuild it?
2 - Am I correct that on a X58 board this should just pop in and and be good to go or is the tape mod still needed?

Thanks

1 - No.

2 - Yes.

sorry for the lack of detail lol

1 - RAID configurations rarely if ever migrate from manufacturer to manufacturer. I know for a fact the intel RAIDS do not work and you would have to wipe the disks and start over on a dell. You need to backup your data, create new array on the perc and then restore from backup.

2 - I have used a 5/i on my x58 board without the tape mod and it works fine.

utnorris · 03-16-09

Thanks for the quick reply. I was afraid of the Raid migration issue, not that big of a deal, I will just clone it to a spare and then create the Raid and then re-clone to it. Thanks again for the quick response.

{core2duo}werd · 03-16-09

from what i have seen no x58 boards need the tape mod, maybe the OP should be updated to reflect this?

ounderfla69 · 03-16-09

Quote:

Originally Posted by utnorris

A couple quick questions:

1 - Will a raid configuration from a ICH10R migrate to the Perc 5i or will I need to clone/rebuild it?
2 - Am I correct that on a X58 board this should just pop in and and be good to go or is the tape mod still needed?

Thanks

1) Its possible for the Intel Raid, I have sucessfully moved a raid 0 raid to the PERC and back to the intel Controller. It should also work for raid 1 but I highly doubt for raid5. You have to set the drive with the same size parameters in the Perc5i Bios. When I moved back to the Intel It just saw it as a raid 0 config.

2) cant tell you

DJZeratul · 03-16-09

Quote:

Originally Posted by ounderfla69

1) Its possible for the Intel Raid, I have sucessfully moved a raid 0 raid to the PERC and back to the intel Controller. It should also work for raid 1 but I highly doubt for raid5. You have to set the drive with the same size parameters in the Perc5i Bios. When I moved back to the Intel It just saw it as a raid 0 config.

2) cant tell you

Sorry, I assumed he meant RAID 5. Yeah, a RAID 0 should go fine.

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PERC 5/i RAID Card: Tips and Benchmarks

03-16-09	#1572 (permalink)
SockMan! New to Overclock.net Join Date: Jan 2009 Posts: 24 Rep: 3 Unique Rep: 3 Trader Rating: 0	A quick google search for "patrol read raid" and I found this: http://www.dell.com/downloads/global...0212-Habas.pdf Basically speaking, they're features that will help reduce the chances of losing data should an array fall into a degraded state. Of course, it only applies to real RAID arrays (not RAID0 or individual disks; neither of which have redundancy or parity). I personally set patrol read to continuous for all my controllers since I don't care as much about performance as data integrity. I don't know what I'll do yet about consistency checks; I think I'll set mine on a weekly schedule.

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