Is this expected performance for Parity-sync?

[snsumner]

Hello,

 

I'm very new to the UNRAID, just purchased UNRAID plus today.  I'm in the process of replacing my existing 2TB (500GBx5) RAID3 system with UNRAID.  My first ever UNRAID system consists of the following:

 

ASUS P4P800 Deluxe Motherboard

Prescott 3.4Ghz P4 (Hyper-thread) Processor

Corsair CMX512-3200C2PRO (400Mhz) 2GB of RAM

NORCO RPC-4020 Hot-swappable Case

Toughpower 750W PSU

Two Promise SATA300 TX4 (Standard PCI slot)

Six Seagate ST31500341AS 1.5TB SATA300 HD

Sandisk Micro Cruizer 4GB

 

Since my motherboard's onboard SATA controller only supports SATA150 I decided not to use it and placed three drives on each of the Promise SATA300 TX4 controllers.  I ran the "hdparm -tT /dev/sda" speed test on each of the six drives and got roughly the same throughput of 1100MB/sec and 110MB/sec.  When I kicked off the Parity-sync it shows that my estimated speed is roughly 20,000 KB/sec and the estimated finish time is around 21 hours.  I'm not fimilar enough with UNRAID to know if this is within an acceptable range or not.  I guess I thought it would take maybe 7-8 hours but I didn't expect 21 hours to do the intial Parity-sync. 

 

The reason I'm using SATA300 controllers on a standard PCI slot is because I had this motherboard, RAM and processor collecting dust.  I wanted to try out my old rig first and see if it gives me acceptable performance.  Right now I'm just looking to stream DVDs and MP3 from my HTPC.  Down the road, I'll likely start going to Bluray and then it might make sense to replace the motherboard and controller to get better throughput if I don't already have to.  For what I'm looking to do will I get decent performance, thats another question I have? 

 

Any comments or suggestions are greatly appreciated.

 

Regards,

Scott

[Joe L.]

Hello,

 

I'm very new to the UNRAID, just purchased UNRAID plus today.  I'm in the process of replacing my existing 2TB (500GBx5) RAID3 system with UNRAID.  My first ever UNRAID system consists of the following:

 

ASUS P4P800 Deluxe Motherboard

Prescott 3.4Ghz P4 (Hyper-thread) Processor

Corsair CMX512-3200C2PRO (400Mhz) 2GB of RAM

NORCO RPC-4020 Hot-swappable Case

Toughpower 750W PSU

Two Promise SATA300 TX4 (Standard PCI slot)

Six Seagate ST31500341AS 1.5TB SATA300 HD

Sandisk Micro Cruizer 4GB

 

Since my motherboard's onboard SATA controller only supports SATA150 I decided not to use it and placed three drives on each of the Promise SATA300 TX4 controllers.  I ran the "hdparm -tT /dev/sda" speed test on each of the six drives and got roughly the same throughput of 1100MB/sec and 110/MB/sec.  When I kicked off the Parity-sync it shows that my estimated speed is roughly 20,000 KB/sec and estimated finish will be roughly 21 hours.  I'm not fimilar with UNRAID enough to know if this within an acceptable range or not.  I guess I thought it would take maybe 7-8 hours but I didn't expect 21 hours to do the intial Parity-sync. 

 

The reason I'm using SATA300 controllers on a standard PCI slot is because I had this motherboard, RAM and processor collecting dust.  But I wanted to try out my old rig first and see if I get acceptable performance.  Right now I'm just looking to stream DVDs and MP3 from my HTPC.  Down the road I'll likely start go to Bluray and then it might make sense to replace the motherboard and controller to get better throughput.  For what I'm looking to do will I get decent performance, thats another question I have? 

 

Any comments or suggestions are greatly appreciated.

 

Regards,

Scott

Sounds a tiny bit slow for an all SATA array, but it is faster than my mostly all IDE based array, and you have 1/3 more space to calculate than me. (My biggest drive is a 1TB)  You are very limited in performance by the PCI bus.  You might be better off putting the parity drive on the motherboard based SATA controller.  (It might be faster, even at 150MB speed, since it is not on the PCI bus)

 

Once parity is initially calculated, it will not be necessary to run a full calculation again, unless you want to do it monthly, as many of us do, to detect problems with the disks, and allow their SMART firmware to detect problems before they result in a disk failure and potential loss of data.  Other than that, you will have plenty of performance for playing movies.

 

Post a syslog and we'll be able to see if everything is working as expected.

Instructions in the wiki: http://lime-technology.com/wiki/index.php?title=Troubleshooting

 

Joe L.

[snsumner]

I stopped the Parity-sync and moved my parity drive to the onboard SATA controller.  The throughput increased from 20,000 to 21,500 KB/sec not really that noticable of a increase.  I was expecting to see somewhere around 50,000 KB/sec and I feel like there is something wrong based on the other benchmark that are published in the wiki.  There is one benchmark using a SATA TX4 that hitting 54,000 KB/sec.  Maybe because I'm using two SATA TX4 on the PCI bus that my throughput is being cut in half.  If this is the case maybe I should upgrade to a PCI-E environment instead?  Another idea is to use both SATA connections on the motherboard and place the remainding four on a single TX4 controller and remove the second TX4 controller. 

 

At this rate it's going to take 20 hours every time I want to run a Parity-sync and I was hoping more for 6-8 hours, bummer.  I've attached my latest syslog while I'm running the second Parity-sync.  Let me know if you see anything that looks wrong in my syslog.

 

 

[Rob_Esc]

Maybe because I'm using two SATA TX4 on the PCI bus that my throughput is being cut in half.  If this is the case maybe I should upgrade to a PCI-E environment instead?  Another idea is to use both SATA connections on the motherboard and place the remainding four on a single TX4 controller and remove the second TX4 controller. 

 

It's my understanding that the PCI bus has limited throughput and will bottleneck data transfer rates. 

 

I run 7 1TB drives on my MB all connected to MB SATA connectors (PCI-E) and my parity runs at 70.

[PhilH]

Unfortunately on my current board all of my sata drives are on the pci bus. My parity checks average about 14,000 with all drives reading. Slow but I can live with it for now. 

[snsumner]

Unfortunately on my current board all of my sata drives are on the pci bus. My parity checks average about 14,000 with all drives reading. Slow but I can live with it for now. 

 

I guess I shouldn't feel so bad that I'm getting 21.5-22MB/sec when you're only getting 14MB/sec.  I think I can live with this type of performance in the next year to come.  Only streamming DVDs and MP3s not likely to push anything else for a while.  I'm going to experiment and move things around to see if I can get better throughput.

[PhilH]

I have zero problems playing anything back. I play High Def mkv & OTA HD recordings easily. I only use a 100Mb lan connection & I can max that out.

[Mopar_Mudder]

I have zero problems playing anything back. I play High Def mkv & OTA HD recordings easily. I only use a 100Mb lan connection & I can max that out.

 

I was going to say the same thing. I think my system is even older then yours, only IDE on the mother board. I have 0 problems playing BluRay on old IDE drives and over a 10/100 network. So if you can live with the long parity checks I woouldn't worry about it.

[snsumner]

Yeah, I can live with it.  The next time I upgrade my gaming rig I'll just give my NAS server the leftovers. ;-)

[lionelhutz]

I'd try something like the parity and drive 2 on the motherboard with one TX4 card.

 

The onboard SATA could be internally on the PCI buss too so using them may really make no difference.

 

The PCI buss is a bottleneck and the buss is shared among the different cards so it is limiting the amount of data being transferred. But then, it could take time to contend with a second card so removing one might help too.

 

Let us know it you find a combo that makes a significant difference.

 

Peter

 

[Mopar_Mudder]

I just started a parity check for the heck of it to see what I was getting. Have (3) 120gig IDE drive on the mother board and (2) 1.5tb SATA drive on a Promise card (PCI Slot)

 

I am getting from 13,700-14,400 average, around 1700 minutes, don't blink you might miss it, LOL

 

So I wouldn't feel to bad if I were you getting 21,000.

 

Just for comparison what are people that have all their SATA on a modern mother board getting to speeds? I problably don't want to know because I will get the upgrade bug then.......

[flambot]

Mine are all SATA (16 in all).  I think my speed is approx 17000 using 2xTX4 cards.  My array takes approx 16 hours to check parity. 

[Mopar_Mudder]

Just check and the Parity is still running but it is up to 63,000 now.

[Joe L.]

Just check and the Parity is still running but it is up to 63,000 now.

You have gotten past the disk block address range of the slower 120Gig IDE drive.  It doesn't have to read it, so speed is no longer limited by it.

[snsumner]

I just started a parity check for the heck of it to see what I was getting. Have (3) 120gig IDE drive on the mother board and (2) 1.5tb SATA drive on a Promise card (PCI Slot)

 

I am getting from 13,700-14,400 average, around 1700 minutes, don't blink you might miss it, LOL

 

So I wouldn't feel to bad if I were you getting 21,000.

 

Just for comparison what are people that have all their SATA on a modern mother board getting to speeds? I problably don't want to know because I will get the upgrade bug then.......

 

I did what you suggested and pulled out one of my Promise PCI TX4 cards and now have two 1.5TB hard drives using the SATA contoller built into the motherboard and the rest on just one of my Promise PCI TX4 card.  I am now seeing throughput of 25,000-26,000KB/sec.  So you are correct that pulling off one PCI controller on the PCI bus actually improved performance by 23%. 

 

After reading my motherboard manual it also recommended that I use PCI slots 4 and 5 first because the other slots share IRQ.  So I put my single SATA card in PCI slot 4 and my ATI Rage PCI video card in PCI slot 5. 

 

When I jump past 6 1.5TB HD and upgrade to UnRAID Pro then I'll migrate to a PCI-E motherboard.  I migrated from a 1.8TB Hardware RAID 3 system to a 7.5TB UNRAID system so it will take me a year or more to fill that up. ;-)

[ReneV]

Another piece of advice (which I originally got from someone here who really knows his stuff, but whose name I can't recall just now) is to stagger the disks across the different controllers, i.e., to not have consecutively-numbered disks on the same controller. I have examples where that has side-stepped some internal bottleneck, for a substantial improvement in parity performance.

 

The worst bottleneck from the perspective of unRAID is the PCI bus, however. It becomes a factor already with 3 or 4 disks, if I remember the calculations correctly, and there's no overcoming that.