Preventing IO Limits on Hard Drives

holygamer

holygamer

holygamer

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I have several 8TB SATA III hard drives. I do a lot of video work. Sometimes if I'm burning 2 Blurays from an image on 1 hard drive, download torrents on another, etc the disc burning will pause saying something like "waiting for hard disk to reach minimum activity level". If I was to stop doing something else like downloading torrents then the burning would immediately continue.

So are there any parts I can buy to prevent IO limits such as this?
 
I'd hazard a guess this is by design in the way your motherboard's SATA controller works and allocates resource to each connected drive. Sounds like your bluray writer's buffers are depleting quicker than they can be filled with new data hence the message you are receiving.

Perhaps a separate dedicated controller card might alleviate these issues, this is not guaranteed but in theory may work.
 
https://www.overclockers.co.uk/showproduct.php?prodid=CC-004-SR&tool=3

This is a two port SATA controller - as I previously mentioned I wouldn't want to lead you up the garden path with my previous post theory as I could well be wrong and there might be something else you could try in terms of configuration in your current set up.

It definitely sounds like your bluray writers buffers are 'under running' data possibly caused by all the other access going to and from your other HD's. Perhaps review the settings in your writing software and ensure their firmware is up to date too.

Also do you defrag your mechanical drives on a regular basis - again in theory a less fragmented drive will reduce amount of time taken to fetch data and could reduce the time your blu ray buffers are waiting for more data. You might also like to see if your SATA controller is set to AHCI mode in your BIOS as this can improve they way your HD's are utilized and accessed by the controller.

Any other folks here able to provide some advice for the OP?
 
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The under running only happens when multiple other programs are accessing the drive/other drives at the same time. Don't think fragmentation is an issue as the drives just have large videos on them so they don't really get fragmented.

I have an 8 Port Supermicro SAS/SATA Card which gives me more SATA III ports. Does your product do something different than just provide extra ports?
 
holygamer said:
The under running only happens when multiple other programs are accessing the drive/other drives at the same time. Don't think fragmentation is an issue as the drives just have large videos on them so they don't really get fragmented.

I have an 8 Port Supermicro SAS/SATA Card which gives me more SATA III ports. Does your product do something different than just provide extra ports?
Click to expand...

The product is just two additional ports so probably won't be of any benefit to you.

I don't have any further suggestions to assist you in this case. All the best.
 
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I can only really point you in the direction of Wikipedia's text on buffer underrun and the explanation it provides. It may just be the setup and demands of your current configuration causing the underrun and is simply placing too much load on a combination of your controller, CPU, available RAM etc. and concurrently accessed drives.

Therefore it is by design, limitation if you will that you experience this issue. The compromise is that your bluray writer has technology to compensate and not spoil your written data as it awaits more to be fetched. Again it's a design feature / flaw of the technology depending on which way you look at it.

It might be possible that matters could be improved if you had a faster CPU and / or additional RAM but unfortunately I cannot make this suggestion with sufficient confidence that it will totally alleviate the symptoms you're experiencing.
 
One final suggestion before I retire, If the read image was stored on an SSD this would probably stop the underrunning of your writers as an SSD is more capable of saturating the SATA3 interface. However if you're constantly deleting the image and replacing for other ones then your SSD will wear out very quickly.
 
It is the design of a mechanical hard drive
They are not optimised for multiple access at the same time
My advice get a second hard drive to use for download only
No controller will ever fix access time
And access times are your problem
Multiple streams of data generating too many requests resulting in bad performance
 
There is a diference in how a SSD works compared to a HDD
A SSD has access times in 0.12ms wille a HDD has 10-20ms
And will be pointless to waste the time to copy between drives
 
tres_kun said:
It is the design of a mechanical hard drive
They are not optimised for multiple access at the same time
My advice get a second hard drive to use for download only
No controller will ever fix access time
And access times are your problem
Multiple streams of data generating too many requests resulting in bad performance
Click to expand...

How does getting a 2nd hard drive for download only fix the issue?

It doesn't matter if several programs are accessing the same drive or each program is accessing 1 drive each. I get the same IO limits.
 
Holygamer, points that spring to mind.

1) Are your drives in SATA or IDE mode. If in IDE you will loose Native Command Queuing, NCQ gives a substantial performance increase and all modern HDD's should support it.

http://en.wikipedia.org/wiki/Native_Command_Queuing

2) Do you have an Intel Chipset, if so are you using Intel RST drivers? Are your drives on the Intel Chipset SATA ports?

3) What make / model are your drives, are they regular consumer drives? Western Digital Black and RAID drives have dual processors to help high IO requests.

4) Do you have HDD write caching enabled in windows?

5) In your Intial post you mention you are doing activity on difference drives but still having IO bottleneck, this suggests to me it's a controller bottleneck and not a HDD bottleneck.
 
I would still check BIOS to endure your in SATA mode and not IDE.

However those WD Greens are are not good for multiple IO, I once installed Windows on a WD Green and remember the computer hanging at time while it was loading windows / apps.

How is your memory, is the computer using PageFile while your having IO issues?
 
I don't know anything about Seagate drives. I only know the WD blacks are good for high IO work.

I can tell you something now to speed the read times on your disks, when I say it almost the entire forum will say no, however trust someone with over 30 years in computers.

Take a USD stick, preferably the fastest you can find, and enable Readyboost.

Readyboost will move small IO request data over to the stick and remove load from all your HDD's.

After you have done this I can show you where the Windows stats are to prove it's working.
 
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