Performance Troubleshooting

[TravisT]

I've been trying to narrow down performance problems I've had with my freenas server for some time now. Transfers are painfully slow when using Lightroom to import RAW photos from an CF card a folder on my local machine to my network share (via Gigabit wired connection). Most of the performance problems seem to be with writes. I finally took the time to go through the performance tuning thread and benchmark my system.

Pool Configuration:
Pool 1: 4 2 TB disks, RAID 1+0
Pool 2: 4x 4TB disks, RAIDZ1

Below are my results:
dd baseline internal test:

Pool 1 - dd if=/dev/zero of=tmp.dat bs=2048k count=50k

1. 51200+0 records in
2. 51200+0 records out
3. 107374182400 bytes transferred in 603.252881 secs (177991993 bytes/sec)

Pool 2 - dd if=/dev/zero of=tmp.dat bs=2048k count=50k

1. 51200+0 records in
2. 51200+0 records out
3. 107374182400 bytes transferred in 39.158605 secs (2742032881 bytes/sec)

NASPT (run in Win7 VM w/ 4GB RAM)
Pool 1 -

Pool 2 -

CrystalMark
Pool 1:

Pool 2:

NAS to Win7 Large File Copy:

1. Pool 1: 104 MB/s
2. Pool 2: 103 MB/s

Win7 to NAS Large File Copy:

1. Pool 1: 115 MB/s
2. Pool 2: 117 MB/s

Does anything look out of the ordinary here? My next step is to do some testing from each client to the NAS. Most of my clients are MacOS - does anyone have guides or recommended software to use to baseline/benchmark?

 

[JohnDigital]

It would appear that pool two is 15x faster than pool one according to the dd test. UDMA7 CF cards can read write data at about ~170MB/s theoretically, so you should be able to transfer to a network share at about the the theoretical ~100MB/s limit of gigabit networking equipment. However, you havent said how you are getting this CF card connected to a computer. It could be that the card interface is USB 2.0 based limiting you to about ~20MB/s or if you are going directly from the camera with a USB cable also could be limiting. Do you have a CF reader operating on USB3? How long exactly does it take to upload a set of photos to the network?

 

[TravisT]

John,
That's a great point that I hadn't even considered, but I omitted some info in my original post. My current image workflow is to import them from the CF card to a folder on my local machine, do some batch renaming, then import them through Lightroom over to the FreeNAS drive (I'll update that above). The import is the slow part. What I have done recently is to import them within lightroom to a local folder, then after they are imported drag them to my network location. This speeds up the process considerably, but not enough that it seems like it's working as it should.

I did a quick test over WiFi (802.11ac) the other day on a Win10 machine and got a whopping 3-4Mb/s transfer rate for a 3-4 Gb iso image - both download and upload. I don't weigh the test too heavily because of the many factors that can affect transfers over WiFi, but it seems extremely slow still.

I agree - something crazy was going on with Pool 1, however, that wasn't the pool that I'm having problems with. Pool 1 was being used as an iSCSI target for my VMs, but that has recently been moved off. It's not serving any files at the moment. I did find it interesting that performance on Pool 1 was slower - I expected it to be faster because of the striped data.

 

[JohnDigital]

Some simple poking around indicates you arent the only one with slow imports to lightroom. Users have complained about large (and small) catalogs taking forever. It looks like your network is up to par with gigabit speed, so in theory it should take about ~10 seconds per gigabyte of uploaded data. But as we all know many gigabytes of small files will take much longer.

 

[TravisT]

Yes, there are definitely some correlations with Lightroom, however I don’t think that’s my only issue given what seems to be slow transfer speeds with other files as well.