New RAID 5, Slow Wr...
 
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New RAID 5, Slow Write Speeds

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(@shadowexecutor)
Posts: 2
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Topic starter
 

Firstly, I am a long time user of SoftRAID for the purposes of building internal RAID sets on Hackintosh rigs for many clients over the past 5 years. Most of my clients are film/video editors or colorists which require high performing RAID sets. This is the very first time I've run into a issue like this. All other RAIDs I've created have worked without a hitch, even when a disk has failed, the RAIDs were rebuilt flawlessly with a new drive replacement. Bravo to the SoftRaid Team!

I am having issues with the write speed of a newly created RAID 5 array on Hackintosh iMac Pro build running MacOS High Sierra 10.13.3 (17D2104) This rig is based on the x299 platform with an 8-core intel i7-7820X processor, 64GB DDR4, and Nvidia GTX 1080 Ti. The main OS drive is a Samsung - 960 PRO 512GB M.2 SSD.

I want you let you know this because I've seen the issue with iMac Pro and the security setting related the SoftRAID drives. On this Hackintosh iMac Pro, that wasn't an issue, the drivers installed to 5.6.5 without a hitch.

The RAID array consists of six 4TB Western Digital Red Pro hard drives. Model number WD4002FFWX. These are fairly new drives, with less than 700 hours of use and absolutely nothing on them.

I have certified all the drives independently prior to creating the raid set. They all passed. I tested the each drives speed individually with Black Magic Disk Speed Test and got speeds of about 200MB/s write/read for each drive.

However, when I go to create a six drive RAID 5 array I am only seeing speeds of 250-350MB/s write and 850-900MB/s read. The read speed is great, it's the write speed that is abysmal. Yes, write cache is enabled. For fun I turned it off and ran tests, write speed dropped to 100MB/s! That is just terrible for a six drive array!

To check if there was something wrong with the drives, I created a six drive RAID 0 array and got speeds of 1145MB/s write and read. Smoking!, but I need the safety of a RAID 5. So I deleted that RAID set and again made and RAID 5. Unfortunately I got the same results. Slow write speed. Then I decided to create a RAID 4, just to see if that would boost performance. Nope, almost identical speeds to the RAID 5.

In another posting I saw the possibility of SoftRAID drivers being quarantined. I checked using the xattr terminal command, and found that SoftRAID app was indeed being quarantined. I followed the instructions to un-quaranten the SoftRAID app and rebooted. With fingers crossed I deleted the previous RAID 5, created it again, and ran the disk speed test. To my dismay, same result... 250-350MB/s write and 850-900MB/s read.

I am a wits end here trying to figure out how to improve the write performance of this RAID 5 array. Please help! Thank you.

 
Posted : 12/03/2018 9:49 pm
(@softraid-support)
Posts: 8006
Member Admin
 

My thought reading this was quarantine. Slow write performance is two things:
Write cache is disabled:
(can be caused by expired trial mode, running the default bundled driver version, disabling the write cache in preferences, or quarantine)
Inadequate CPU horsepower:
(example, the older Mac Pro machine processors are not fast enough to handle parity data quickly enough, so write performance is weaker. Same with Mac Mini's, etc.) Your 8 i7's are certainly fast enough.

Neither of these appear to be the cause. Send us a support file at support at softraid and we can see if we can figure anything out.

 
Posted : 13/03/2018 1:09 pm
(@shadowexecutor)
Posts: 2
Member
Topic starter
 

My thought reading this was quarantine. Slow write performance is two things:
Write cache is disabled:
(can be caused by expired trial mode, running the default bundled driver version, disabling the write cache in preferences, or quarantine)
Inadequate CPU horsepower:
(example, the older Mac Pro machine processors are not fast enough to handle parity data quickly enough, so write performance is weaker. Same with Mac Mini's, etc.) Your 8 i7's are certainly fast enough.

Neither of these appear to be the cause. Send us a support file at support at softraid and we can see if we can figure anything out.

I have sent a support file email to the address listed. Thank you

 
Posted : 13/03/2018 2:45 pm
(@softraid-support)
Posts: 8006
Member Admin
 

It does appear that there is a SATA issue, as you noticed 4 disk RAID 5 was OK, but 5-6 disk volumes started slowing. Strange issue.

 
Posted : 13/03/2018 5:10 pm
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