Preventing IO Limits on Hard Drives

holygamer · 12 May 2015 at 23:27

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?

holygamer · 12 May 2015 at 23:35

Can you suggest a product?

holygamer · 13 May 2015 at 00:11

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 · 13 May 2015 at 00:22

OK thanks. So is there no product I could install to increase the bandwidth?

holygamer · 13 May 2015 at 00:33

OK thanks for your help.

holygamer · 13 May 2015 at 01:04

I don't use SSDs as they're too expensive for large storage. I use SATA III 3.5inch hard drives.

holygamer · 13 May 2015 at 01:06

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

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 · 13 May 2015 at 04:31

2: Yes
They are WD Green 4TB. Yes I have write caching enabled.

holygamer · 13 May 2015 at 04:39

They are in SATA mode. I'm replacing all my drives with Seagate 8TB Archive drives. Are those any better with regards to IO requests?

holygamer · 13 May 2015 at 04:49

OK I've done that. So where do I find the stats to show it's working?

holygamer · 13 May 2015 at 10:26

I've got a cable connected to my power supply. Other end is 2 x molex 4 pin to sata power. Then I have 1 Silverstone Sata Power to 4 Sata power Silverstone (has capacitor on it) connected to that. I have 4 3.5" 8TB hard drives connected to that. If I remove one of the drives and connect the SSD C Drive, the drive works.

On the other molex I have the same thing - another 4 drives

I've also got another cable connected to my power supply. Other end is 2 x molex 4 pin to sata power. I have a a 4 x Sata power cable (no capacitor on the cable) connected to that. Two Bluray writer drives are connected to that cable. Two SSDs are connected to that cable. One SSD is a data drive. All drives work apart from the C Drive. Bizarrely if I disconnect the Bluray drives and data drive and only connect the SSD C drive to that cable, it STILL doesn't work! But it does work if I replace that cable with a Silverstone one with a capacitor in it!

Is that normal? A while ago I bent some of the Sata power pins by forcing a cable onto the C Drive. I bent them down back in place so I can still connect a sata power cable to it but there's still not completely flat. Could that be what's causing the issue?

joeyjojo said:
This is a good point, see if you can enable preallocating files in your torrent prog OP.

As for "waiting for hard disk to reach minimum activity level", if you're certain that dedicated different drives for different tasks isn't going to help then the only thing to do is to buy more drives and set them up in an array to increase the bandwidth. A (preferably hardware, might involve buying a card) RAID 5 array (min. 3 drives, the more the better) would give you n times the read performance and n-1 times the write performance, with tolerance for losing 1 disk.

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

That sounds interesting. I don't really understand anything about RAID and how doing what you said would improve performance. Is there a guide somewhere?

holygamer · 14 May 2015 at 19:34

lude1962 said:
'I've got a cable connected to my power supply. Other end is 2 x molex 4 pin to sata power. Then I have 1 Silverstone Sata Power to 4 Sata power Silverstone (has capacitor on it) connected to that. I have 4 3.5" 8TB hard drives connected to that. If I remove one of the drives and connect the SSD C Drive, the drive works.

On the other molex I have the same thing - another 4 drives'

8 drives off one cable !!!!!!!!!!

Do you have some sort of proof that says you can't run 8 drives off a cable? Because it works perfectly fine. It's just that when I try and connect my C Drive it doesn't work.