Slow/inconsistent network performance on RAID 5 --- RAID 0 unaffected
I'm having a strange issue that may or may not be related to SoftRAID. I have a 2018 Mac mini, (Mojave) setup with a 5-drive RAID 5, (12TB WD SAS HDDs) and 2-drive RAID 0, (2TB Samsung SATA SSDs). These two raids have similar performance locally, (both around 1GBps read/write) with the RAID 5 being slightly more inconsistent which is expected.
I've setup 10gb Ethernet between the mini and my 2020 iMac, (Catalina) and I've turned on file sharing over SMB. The RAID 0 performs almost identically over the network as it does locally, but the RAID 5 performs very inconsistently on both reads and writes with the read performance averaging around 1/3 of the local performance and the write just dropping to 0MBps for seconds at a time, (see attached graphs).
I originally thought there was some kind of network issue as I had read that file sharing on Mac has had issues recently but that doesn't explain why the RAID 0 SSDs hold performance so well over the network.
If anyone has insight into what would cause this I would love to hear it!
I do know there is a 10GB ethernet bug, but I have not stayed on top of it. What ethernet cards are you using?
@softraid-support I'm not experiencing very slow performance on all of the shares... only on the RAID 5 disk array. The RAID 0 performs consistently well over the network. If this were a Mac OS bug wouldn't all of the shares be affected?
The bug that happens with 10G is with Mohave and was fixed in Catalina. Any chance you can upgrade the Mini to Catalina?
Do that and let me know. If you still have an issue, I will give you a set of tests to try, so we can isolate what is happening better.
When I'm transferring to/from the RAID 0 over the network the speeds are good. On the RAID 5 I'm seeing better writes then read speeds. Writes are close to 1GB/s (which is near the local speed) and mostly consistent but reads are inconsistent and average around 250-300MB/s, (about 1/3 or 1/4 of local speed).
Lets try it this way. If you unmount/swap the two enclosures, does the slow read speed follow the drives, or the ethernet connection?
(trying to isolate whether this is a volume issue, or a ethernet traffic issue.)
If it is the volume then this will repeat when you swap the enclosures.
Both the RAID 5 and RAID 0 are in one enclosure so I can't test them separately but I can unmount them and just test the speeds to/from the mini's boot SSD which should accomplish the same thing:
The speeds are close to maxing out the 10Gb network at ~1.2GB/s read & write.