unraid array speed question

[orkid1989]

i am using unraid on a old lenovo s30 workstation with a xeon 1620v2 and 32gb of ddr3 ecc ram. did notice that after i bought it the thermal paste on it had turned to concrete so i cleaned it and replaced with thermal grizzly. hoping it wasnt cooked. anyways it also has 2 6tb and 1 2tb ironwolf drives in the array (sata 2). a 500gb samsung ssd and a 120gb kingston ssd in the cache (sata 3). i am running a vm that is for dedicated game servers. so it is not actually playing the games. but it seems like the performance is really lacking. my question is what should i expect to get in read/write speeds on the array vs the cache? i am currently averaging in the single digit mbps and occasionally it will jump up to the double digit range. max i have seen is 30mbps. i already turned on turbo write mode. any ideas or suggestions?

[orkid1989]

[Electronics Wizardy]

Try running something like crystal disk info.

 

What is the load in linux? Try sshing in and running htop and looking at disk usage with iostat.

[beyonddc]

• First thing first, you are mixing a 500GB and a 120GB SSD in your cache pool.  When mixing different size of hard drives for your cache, the smaller drive wins so essentially your cache is only 120GB large.
• If you need read/write performance then you should put your VM outside of the array.  You should install the unassigned device plugin on your Unraid server so that you can save your VM image to a drive outside of your array.

[orkid1989]

19 minutes ago, beyonddc said:

• First thing first, you are mixing a 500GB and a 120GB SSD in your cache pool.  When mixing different size of hard drives for your cache, the smaller drive wins so essentially your cache is only 120GB large.
• If you need read/write performance then you should put your VM outside of the array.  You should install the unassigned device plugin on your Unraid server so that you can save your VM image to a drive outside of your array.

O ok well I was thinking about replacing the 120gb with a 1tb but I guess that would run into the same bottleneck? Also the cache is in raid 0 if it matters. As far as I can tell I'm not really using the cache because everything is going to the 2tb hdd.

 

If I installed the plugin can I possibly move the 2tb drive outside the array or would it reformat it?

[orkid1989]

32 minutes ago, Electronics Wizardy said:

Try running something like crystal disk info.

 

What is the load in linux? Try sshing in and running htop and looking at disk usage with iostat.

It is a windows 10 vm. I'll try crystal disk and see

[orkid1989]

Also am I missing the purpose of array and cache?

[Electronics Wizardy]

15 minutes ago, orkid1989 said:

Also am I missing the purpose of array and cache?

what is the vm installed on? Id just put the vm on the cache drives only

[orkid1989]

22 minutes ago, Electronics Wizardy said:

what is the vm installed on? Id just put the vm on the cache drives only

Vm is on drive 1. It wont currently fit on the cache drives. Also I just ran crystal disk and the numbers are substantially higher then what I'm getting. Any ideas?

[Electronics Wizardy]

1 hour ago, orkid1989 said:

Vm is on drive 1. It wont currently fit on the cache drives. Also I just ran crystal disk and the numbers are substantially higher then what I'm getting. Any ideas?

That might be a ram cache.

 

The parity of unraid is very slow. If you want fast vm performance look at a different hypervisor like proxmox, you can get a much faster array.

[orkid1989]

what is the purpose of the array? i thought it was just like a pc with multiple drives and you can set it up in raid configuration. and i thought cache was for temporary file download or frequently accessed files. but seems more like just a different type of storage separate from the rest.

[beyonddc]

19 hours ago, orkid1989 said:

what is the purpose of the array? i thought it was just like a pc with multiple drives and you can set it up in raid configuration. and i thought cache was for temporary file download or frequently accessed files. but seems more like just a different type of storage separate from the rest.

Unraid is not a raid server.

The array is just a collection of hard drives that you can configure and create network share.  To provide fault-tolerance, a designated parity drive is needed.  The parity drive must be a drive that is bigger than or the same size of your largest drive in your array.  You can have up to 2 parity drives in an Unraid server.  With one parity drive, you can recover your array if one drive failed.  With two parity drives, you can recover your array if one or two drives failed at the same time.

 

If your share is configured to use the cache drive then it would be used as a temporary storage.  A scheduled task will be run middle of the night and move your files from the cache back to your array.  The cache is used to increase I/O performance because writing directly into the array with parity check can be slow.

 

My explanation is probably not as good to what's in the Unraid Wiki.  I suggest you to read section

1 What is Unraid?

1.1 Network Storage Storage

1.1.1 Parity-Protected Array

1.1.2 User Shares

1.1.3 Cache

https://wiki.unraid.net/UnRAID_Manual_6#Network_Attached_Storage