Internal Marvell RAID vs. external RAID

[VelcroFace]

Due to the massive amount of data I'll be ingesting on a new video project, it looks as if I need to expand the capacity of my system by about 16TB. One option is to install two enterprise-class 8TB drives internally, connected to the Marvell 9128 controller on my motherboard (ASUS P9X79 Pro), and configure them as RAID 0. (I need RAID 0 because I will be working with 5K RED camera files.) Another option is to purchase an external RAID drive, such as the Western Digital MyBook Pro, which has both USB 3.0 and Thunderbolt ports. Which option would result in faster read/write speeds? Do you know if the Marvell 9128 controller on this board even supports drives as large as 8TB?

 

[R_1]

2 8TB drives from what I have read transfer max around 250MBps even doubled the SATA III (600MBps) bus should be able to handle 2 drives on RAID0.

as to externals there is not much need for thunderbolt if each drive cannot saturate even half the bus SATA III offers. your motherboard has 2 eSATA ports on the back. I would suggest this as the external connector as long as 2 drives is the max. larger external enclosures with more drive will be able to saturate the SATA III bus and thunderbolt would be needed.

the main issue for read and write speeds in this situation are the drives themselves, eSATA or thunderbolt will do fine, 2 drives on USB 3.0 can saturate the bus, which slows the works. the drives should be the slowest part of the setup. a single eSATA BUS can support and handle 2 8TB drives concurrently, not three though three will bump against the buses limits, three drives thunderbolt or USB 3.1 at 10Gbps

I could find no reference to a maximum drive size for the controller.

I would say 2 drives internally would yield the fastest performance, as you can choose the fastest drives.

 

[VelcroFace]

Your motherboard has 2 eSATA ports on the back. I would suggest this as the external connector as long as 2 drives is the max. larger external enclosures with more drive will be able to saturate the SATA III bus and thunderbolt would be needed.

Thanks for your detailed and enlightening explanation. I currently have a SansDigital TowerRAID TR4UTBPN 4-bay external RAID enclosure on one of those eSATA ports. It's loaded with four 2TB enterprise-class drives in RAID 5 for a total of 4TB with a hot spare. The fastest speed I can eke out of it reading 2K video files is 210 MB/sec. That may be due to it being SATA II, even though the drives are SATA III. Should I scrap that enclosure and get a newer one that handles SATA III?

I also have a WD MyBook Duo 16TB drive on a USB 3.0 port reading 2K video at 240 MB/sec. I'm thinking of using that as backup for a drive that has read speeds in excess of 340 MB/sec., which is what the MyBook Pro promises to deliver.

As for using the motherboard's Marvell controller, I could find nothing in the Marvell datasheet that limits the size of the hard drives. However, I downloaded the user manual for a RAID card that uses the same Marvell chip, and it specifies HDD sizes up to 2TB. The screen shots are identical to those in the ASUS user manual for this board, as it pertains to the Marvell controller configuration. If that controller does indeed have a 2TB limit, I suppose I could purchase a PCI express card. Your advice would be appreciated.

 

[R_1]

I'm pretty sure that 2TB was the largest drives available when the controller came out, marketing speech for large drive support.

if you replace the TowerRaid 4 bay the new SATA III system will allow the drives to work at full speed, they are hobbled by almost half, SATA II 300MBps, SATA III 600MBps.

My first thought was to get a big crazy fast SSD, and use it as a cache for the drives. your motherboard support this (SATA III drives only) without need for extra software or special SSD's. I use a Crucial Adrenaline Cache SSD. my nephew uses FancyCache software.
plug in the drives and the motherboard will combine them into a single drive as far as the OS in concerned. Depending on the file sizes used this may increase overall performance on at least one drive (adrenaline and your motherboard only support single drive solutions), some SSDS only have a small high speed cache and if the files are larger than this cache @2GB the SSD's will hit a wall and revert to HDD speeds.

Price is no Object - I would suggest a 512GB NVME SSD on a PCIe card, using fancy cache (fancy cache is the trial version 6 month-Primo cache is the retail version @$30), to cache all the system drives.
the Crazy high speeds allowed by the cache should alleviate the R/W issue. NVME drives are expensive but transfer @ 2.2GBps Read - 1.2GBps Write

 

[VelcroFace]

My first thought was to get a big crazy fast SSD, and use it as a cache for the drives. your motherboard support this (SATA III drives only) without need for extra software or special SSD's.

That's a good idea, and perhaps I'll implement it for future projects. However, I need not only speed but a minimum of 12TB capacity to handle the media for this project.

The more I read about internal versus external RAID, the more I believe that software RAID might work better in this situation. I could add two 8TB drives internally, configure them as RAID 0 in Windows Disk Management, and get faster speeds than connecting to an external drive through USB 3.0. What's your opinion?

 

[R_1]

I agree, internally the drives will have their own speed limits not sharing one bus between them.

 

[VelcroFace]

I agree, internally the drives will have their own speed limits not sharing one bus between them.

Would I be better off buying two 8TB SAS drives, along with a RAID SAS PCIe card? SAS drives are rated at twice the throughput of SATA drives. Would this make a difference on my system?

 

[VelcroFace]

Well, I finally bought two Seagate 8TB Enterprise-class SATA drives (ST8000NM0055), installed them on two of the four Intel 3Gb/sec ports of my ASUS P9X79 Pro motherboard, and configured them as RAID 0 through Disk Management in Windows 7. I immediately got read speeds of 420 MB/sec, which is not too shabby. Now that I've copied the video media onto that drive, with 30% free space available, the read speed has slowed to about 300 MB/sec. That is a considerable decrease in speed. Is that normal? What might be causing this slowdown?

I first installed the drives on the motherboard's two Marvell SATA ports, which are rated at 6 Gb/s. However, Windows 10 would not allow me to boot up Marvell's configuration utility at POST. So I tried striping the drives through Windows Disk Management. That worked, and the read speed was impressive (425 MB/sec). However, the write speed was terrible (175 MB/sec). What's more, suddenly all the drives on my system showed up as removable devices.

I tried restoring my system using an image I had made with Macrium Reflect, but the drives still showed up as removable devices. Figuring that installing those two new drives had changed something in the BIOS, I updated it to the latest version, disabled the Marvell controller, and then restored my system using an image I had made under Windows 7. That's why I'm now running Windows 7. The new Seagate Enterprise drives seem to be working fine, but not as fast as I had hoped. In fact, the WD 16TB My Book Duo (which I am now using for backup) actually gives me slightly faster read times.

 

[harrysmellington]

Well, I finally bought two Seagate 8TB Enterprise-class SATA drives (ST8000NM0055), installed them on two of the four Intel 3Gb/sec ports of my ASUS P9X79 Pro motherboard, and configured them as RAID 0 through Disk Management in Windows 7. I immediately got read speeds of 420 MB/sec, which is not too shabby. Now that I've copied the video media onto that drive, with 30% free space available, the read speed has slowed to about 300 MB/sec. That is a considerable decrease in speed. Is that normal? What might be causing this slowdown?

I first installed the drives on the motherboard's two Marvell SATA ports, which are rated at 6 Gb/s. However, Windows 10 would not allow me to boot up Marvell's configuration utility at POST. So I tried striping the drives through Windows Disk Management. That worked, and the read speed was impressive (425 MB/sec). However, the write speed was terrible (175 MB/sec). What's more, suddenly all the drives on my system showed up as removable devices.

I tried restoring my system using an image I had made with Macrium Reflect, but the drives still showed up as removable devices. Figuring that installing those two new drives had changed something in the BIOS, I updated it to the latest version, disabled the Marvell controller, and then restored my system using an image I had made under Windows 7. That's why I'm now running Windows 7. The new Seagate Enterprise drives seem to be working fine, but not as fast as I had hoped. In fact, the WD 16TB My Book Duo (which I am now using for backup) actually gives me slightly faster read times.

How are you finding read speed, are you testing specific files or sequential sectors? As a HDD is a disk media, if the sectors that contain 1 file are spread physically far apart on the disk then this will effect read time of that file. Furthermore the method used by the RAID controller to consolidate the data may have a decrease in performance as the amount of data stored increases but this is pure speculation.

 

[VelcroFace]

How are you finding read speed, are you testing specific files or sequential sectors?

To test the read speed I am using AJA System Test, which simulates how your system handles various video files. In this case, I tested a 5K RED file 4GB in size.

 

[harrysmellington]

How are you finding read speed, are you testing specific files or sequential sectors?

To test the read speed I am using AJA System Test, which simulates how your system handles various video files. In this case, I tested a 5K RED file 4GB in size.

Ok so I would suggest trying the following:

Create a partition on the RAID and test it, then fill it and test again, see if you can duplicate the drop in performance. Then run Defrag on it and see if that helps.

If you find that performance increases i would suggest updating the BIOS, also make sure you have all windows updates installed, look up win 7 convenience rollup. Also Defrag the rest of the drive of course.

It could just be the nature of the beast that you'll see some drop in performance, i'm no expert on HDD operation but from what i've seen online the disk reads faster as it approaches the edges (don't take my word for it though) and so as you write to the drive it will become slower (as sectors are written further inward). This effect would be doubly felt in RAID 0.

 

[VelcroFace]

If you find that performance increases i would suggest updating the BIOS, also make sure you have all windows updates installed, look up win 7 convenience rollup. Also Defrag the rest of the drive of course.

My motherboard has the latest BIOS, Windows 7 has all its updates, and Disk Defragmenter reports that my 16TB dynamic disk is 0% fragmented. Seems I've done everything possible, except for installing a dedicated RAID controller card. However, I've read that overhead is negligible for software RAID 0 or RAID 1.

 

[harrysmellington]

If you find that performance increases i would suggest updating the BIOS, also make sure you have all windows updates installed, look up win 7 convenience rollup. Also Defrag the rest of the drive of course.

My motherboard has the latest BIOS, Windows 7 has all its updates, and Disk Defragmenter reports that my 16TB dynamic disk is 0% fragmented. Seems I've done everything possible, except for installing a dedicated RAID controller card. However, I've read that overhead is negligible for software RAID 0 or RAID 1.

If that's the case then I think it's just the drives themselves. I don't think there is anything particularly wrong with them. If the performance is unacceptable you should look into SSDs. There are 4TB SSDs out there now but they're almost $2000 a pop.

What I would suggest to you is to find your largest project and use an SSD or array of SSDs that will fit this project and load the data into the SSD before working on it.