Hi, I've recently expanded the number of drives in my system and now see parity rebuilds happening at 1/2 the speed it did before. Hoping for some help on where to physically connect each drive please! Old parity rebuild was at 100/120 MB/s, hoping to achieve that again.

 

Base Computer came from a Lenovo thinkstation s20 with quad core xeon. 24GB EEC Ram installed. https://support.lenovo.com/ca/en/solutions/pd005642

5 onboard SATA 2 connectors. (Based on speed even of SATA2 I don't think this would be my bottleneck as sata 2 is theoretically maxed at 300MB/s)

2x 4 port SATA cards - 1: IOCrest SI-PEX40064, 2: QNINE PCIe SATA Card . Both report Marvell chipsets but don't know which ones. Both cards are supposed to be sata 3, and are installed in 1x slots. I'm wide open to buying new cards if that is my issue. Suggestions please.

 

Drives: All Spinning disks are WD Reds of various ages, but all are SATA 3.

 

Cache Drives: 2x 256 GB SSD BTRFS (Samsung Evo). My large writes (mp4/mkv mostly) write directly to the array so speed is not critical here. Plex and all my dockers are here, and one Windows VM, none of which require huge speed.

Parity: 1 x 10TB

Spinning disks in array: 1 x 10TB, 4 x 4TB, 2 x 3TB, 1 x 2TB

All upgrades in future will be to 10TB Reds as I need more space. not planning to expand to more drives.

 

Outside array (unassigned devices): 1x 256 GB SSD, 1x 2TB. I don't care how fast these drives are - they're temp drives for video editing and one Windows VM on SSD. 

 

Can you please suggest where to connect each drive for maximum array read performance?

 

I'll be unable to read or respond for a few days... I look forward to your suggestions! thanks.

 

Tiwing.

 

 

 

 

Edited August 8, 20196 yr by tiwing

PCIe 2.0 x1 controllers with 4 disks will bottleneck, but still should be able to do around 100MB/s, if you're getting much less than that try the Unraid tunables tester script.

 

For best performance you'd replace those Marvell controllers with an LSI HBA, assuming you have a x8 or x16 slot available.

 

 

is it possible, given that the drives are WD Red, that write cache is off? My WD Reds need write cache enable after each and every reboot, i've not yet figured out how to make it persistent (anybody?).  And, my parity checks ran at a low speed until i re-enabled write cache so worth a quick check if you're running those drives..

 

 

Edited August 9, 20196 yr by superloopy1

4 minutes ago, superloopy1 said:

My WD Reds need write cache enable after each and every reboot, i've not yet figured out how to make it persistent (anybody?).

Install the User Scripts plugin and use that to set up a script containing the required commands that is set to execute the first time the array is started after each boot.

Just now, itimpi said:

Install the User Scripts plugin and use that to set up a script containing the required commands that is set to execute the first time the array is started after each boot.

I've no idea on how to construct or what to include in a script although i see the principle involved.

 

Non-linux person unfortunately.

 

Are there any scripts or guides out there?

thanks for the suggestions - will dig into write cache in the next few days and will post up if I find anything out. Thanks!

write cached is OK. I suspect it's all related to the 1x slots. Saving my pennies for the LSI SAS card.. it's not critical to get this "fixed" so I'll prob wait for a year or so. Thank you all for your help. Mods, feel free to close the thread...

Edited August 16, 20196 yr by tiwing