November 5, 20169 yr Hey Guys, I just got 2 Mellonex Connectx-2 10gig adapters and a DAC to connect my new main rig to my server. My main rig is a 6700k, 512 m.2 SSD, 32GB DDR4. My server is an E3-1225-V3, 32GB DDR3 with the following drive layout. My main issue is that when I start a transfer from my main rig to the server it will saturate the 10gig connection for about the first 5GB of data. I understand it's more than likely writing the file to the ram cache that unraid uses. Once I pass that 5GB mark it slows to a literal crawl. We're talking about 30-60MB/s. I'm not using the cache for this share that i'm writing to and that's not really an option for me since I use the cache for other things. I also get really slow transfer speeds when going from my server to my main rig, 50-80MB/s. I have set all of the driver setting I should have based on this YouTube video I'm wondering if the dual parity is the issue i'm running into because having 8 disks should have better speeds than this. Thanks!
November 5, 20169 yr Once you've filled up the spare RAM you're writing directly to the parity protected array and the figures you are seeing are as good as you can expect for read-modify-write parity operations. Using the cache would improve write performance - that is, after all why it was originally introduced. Since you don't want to do that you could enable Turbo write with Settings -> Disk Settings -> Tunable (md_write_method) -> reconstruct write.
November 5, 20169 yr Hey Guys, I just got 2 Mellonex Connectx-2 10gig adapters and a DAC to connect my new main rig to my server. My main rig is a 6700k, 512 m.2 SSD, 32GB DDR4. My server is an E3-1225-V3, 32GB DDR3 with the following drive layout. My main issue is that when I start a transfer from my main rig to the server it will saturate the 10gig connection for about the first 5GB of data. I understand it's more than likely writing the file to the ram cache that unraid uses. Once I pass that 5GB mark it slows to a literal crawl. We're talking about 30-60MB/s. I'm not using the cache for this share that i'm writing to and that's not really an option for me since I use the cache for other things. I also get really slow transfer speeds when going from my server to my main rig, 50-80MB/s. I have set all of the driver setting I should have based on this YouTube video I'm wondering if the dual parity is the issue i'm running into because having 8 disks should have better speeds than this. Thanks! You have a very peculiar definition of "a literal crawl", 30-60MB/s is perfectly reasonable when writing to a non-SSD parity protected array, no matter if it is dual or single parity. Reconstruct write/turbo write might be able to speed things up a bit, don't know if you have explored that. Other than that, given that you refuse cache disks, you could buy more RAM, get faster disks and/or skip parity completely if you want faster writes. As for your slow reads, some of your disks seem to be quite small, which probably means they are quite old. I would not expect miracles reading from those. Not quite sure what does having 8 disks have to do with anything. Sounds like you expect unRAID to do striping. It doesn't. One file is written to/read from one disk, not 1/8 from each disk.
November 5, 20169 yr Hey Guys, I just got 2 Mellonex Connectx-2 10gig adapters and a DAC to connect my new main rig to my server. My main rig is a 6700k, 512 m.2 SSD, 32GB DDR4. My server is an E3-1225-V3, 32GB DDR3 with the following drive layout. My main issue is that when I start a transfer from my main rig to the server it will saturate the 10gig connection for about the first 5GB of data. I understand it's more than likely writing the file to the ram cache that unraid uses. Once I pass that 5GB mark it slows to a literal crawl. We're talking about 30-60MB/s. I'm not using the cache for this share that i'm writing to and that's not really an option for me since I use the cache for other things. I also get really slow transfer speeds when going from my server to my main rig, 50-80MB/s. I have set all of the driver setting I should have based on this YouTube video I'm wondering if the dual parity is the issue i'm running into because having 8 disks should have better speeds than this. Thanks! The basic answer is that you do not have an issue.. Bottleneck is the parity protection of your array. The speeds you are getting are perfectly fine.. If you wnt to go faster you could enable turbo writes, this will speed up your complete array instead of only the disk you are writing to. I suspect that you will still think this is slow.. If you need more speed and you want to stay with unraid you can start using a cache disk, but you have stated that is not an option for you. Remaining option is to skip parity alltogether, which would be a bad idea.. If all of that is not an option you need to look for a different solution... Significantly faster speeds can be got from other types of arrays, they perform striping meaning one file gets written to the complete array (part of the file on every disk), that speeds things up. There are a lot of options out there that do this. The reason we are using unraid is that we specifically do not want that.. With unraid every disk contains readable data meaning that even with catastrophic drive loss you can still recover all the disk that did -not- die. With a more speedier RAID array you loose all data if you lookse X disks (mostly 1 or 2, depends on your config). The penalty for that extra security is a hit on speed.
November 5, 20169 yr Author Lots of help! I'm relatively new to Unraid and I did not know that it didn't strip data across multiple disks. I'm going to rethink my cache issue. Don't know if I want to chance not having a parity drive.
November 5, 20169 yr Lots of help! I'm relatively new to Unraid and I did not know that it didn't strip data across multiple disks. I'm going to rethink my cache issue. Don't know if I want to chance not having a parity drive. I have 500GB in cache and use that for my dockers, vm's AND for the cache drive.. It never fills up.. Works really fine.. And the cache drive function combines nicely with the appdata/docker/vm stuff, its not in each others way.. Success !
November 5, 20169 yr Author Bit the bullet and will change the way I use the cache so i threw in 2 more SSD's and put them in a raid 0 btrfs. Full 10GB constantly. Feels good man.
November 5, 20169 yr How did you 'use cache'? My guess is that your' use' need would have been fulfilled with unassigned devices
November 5, 20169 yr My guess is that your' use' need would have been fulfilled with unassigned devices Really? How? It doesn't meet this requirement: Don't know if I want to chance not having a parity drive.
November 7, 20169 yr Author Bit the bullet and will change the way I use the cache so i threw in 2 more SSD's and put them in a raid 0 btrfs. Full 10GB constantly. Feels good man. I was using the cache for my Lightroom catalog and pictures. I have since changed that. I also enabled direct io in the global share settings.
Archived
This topic is now archived and is closed to further replies.