I've been trying to find this information by search but just having one of those days so figured I'd just ask.

 

I am about to start my first unraid build. I know people lose it for large media storage but I'm looking to use it as basically a NAS between four computers to store files that get worked on by different people -- mostly Illustrator / Corel Draw / Photoshop / InDesign / Excell and PDFs. Roughly how would performance compare to having the files on the computer itself?

 

Assumed 5400 Reds as the drives / plenty of CPU for unraid / gigabit switch

 

 

Not nearly as good as SSD on local machine due to network.

 

Read on HDD may be comparable since GBe can mostly keep up with spinners.

 

Write to a cache disk will also be GBe speed.

 

Write to a parity protected disk will be about 1/3 due to parity operations.

Generally read speeds of larger files are in excess of 80MS/sec.  Reading large numbers of small files is probably below that due to the overhead. 

 

Write speed directly to the array (no cache drive) vary depending on the amount of RAM installed.  (Excess RAM is used a RAM cache until it is full.)  I see write speeds of about 40MB/s ( after the RAM cache is filled) on large files.  Large number of small files is slower because the overhead to create the file and determine where to actually store the file on the disk.  While I don't have a cache, my reading suggests that is will be at or above 80MB/s on large files.

 

By the way, the numbers also assumes that you keep the disks spun up all of the time.  (A lot of us have the unused disks spin down to save both energy and wear-and-tear on the drives.  When you spin down the unused disks, when you make a request for file access the disk will have to spin up before the transfer can begin.)

Thank you  trurl and Frank1940.

 

Yeah I figured it wouldn't be anywhere near SSD speeds but I was hoping to be at least the same as a mechanical drive

 

I found a topic where someone was getting 110 MB/s from unraid and most people thought that was really good as they were getting 70-80 MB/s. That is faster than a mechanical drive so it should be workable.

 

I was planning on having a SSD as cache disk as long as it transparent to the operation of the array.

 

 

 

 

 

I was planning on having a SSD as cache disk as long as it transparent to the operation of the array.

 

The files are the cache will appear to be a part of the user share as soon as they are saved.  It should be pointed out that these files on a single SSD drive will be unprotected until  mover  moves the files from the cache to the array.  Mover normally operates overnight when the server is likely not to be in use. 

 

You can set a cache array using two SSD drives  if you want the files to protected as soon as they are written to the server.  Speeds to this type of array will be comparable to a single SSD drive. 

I have actually been playing with the idea of doing an all SSD array.

 

Basically my goal is to have a big unraid at home which is my media server and a small array at the office (office and home are connected by a VPN and I get a 6-7 Mbps connection between them). Since my storage requirements for stuff I need to access frequently is minimal (well under a TB) I was thinking maybe an all SSD array at the office would be better.

 

Looking for topics on this I found three about people considering it but the community seemed to think it was a waste mostly because of throughput limitations. The topics were also older when SSD was still much more expensive. Given that I can get good SSDs for the same price as the Reds and using the Reds 75% of the space is going to be unused I'm thinking a SSD array is the way to go to avoid the spin-up delay. I've already ordered the Reds but I can just use them in the home array.

 

The other option I'm considering is continuing with the build using the Reds but then using OwnCloud to keep copies of the files on the individual machines (at least on the one that is going to access them 90% of the time). Major disadvantage there is that I don't know how fast the files sync -- using Dropbox this way even with LAN sync it seemed there was too much of a delay and Dropbox does delta sync which I don't believe OwnCloud does.

 

The actual best solution would be to build a SSD unraid with a VM for Windows 10. That way the other machines using the files would just access them on the array -- there would be no spinup delay plus speed would be just limited by the network plus the person accessing them via the VM wouldn't have the throughput limitation and since that machine uses the files the vast majority of the time. Only drawback to this is after looking at setting up VM I was concerned it might be above my level of competence.

Wiki: Do not assign an SSD as a data/parity device

Thank you.

 

Well that removes some options.

Although unsupported I’ve been using SSDs on my test server for a while and there were never any unexpected sync errors, trim would almost certainly invalidate parity but Unraid doesn’t allow trim on an SSD that is part of the array, that leaves SSDs internal garbage collection, I purposely tried to provoke it and couldn’t, this does not mean it can’t happen, but there are a few users using at least one SSD as an array drive and never reported any sync errors.

 

In the end I would say that it *should* be safe, but in the beginning you should do frequent parity checks, if there is a single sync error then stop, note that even if there are sync errors you would only lose/corrupt data in the event of a rebuild if one of the SSDs failed.

 

I have actually been playing with the idea of doing an all SSD array.

 

Basically my goal is to have a big unraid at home which is my media server and a small array at the office (office and home are connected by a VPN and I get a 6-7 Mbps connection between them). Since my storage requirements for stuff I need to access frequently is minimal (well under a TB) I was thinking maybe an all SSD array at the office would be better.

 

 

Is this VPN speed the proper number?  Because if it is, any unRAID array will support direct writing to the array using any modern spinning hard disk (without the use of a cache--  SSD or cache). I know a lot of folks (Myself included at times) will confuse Mb/s  (megabits per sec)  with MB/s (Megabytes per sec). 

 

I believe you will actually find that most people have decided that the network is the limiting problem to throughput via unRAID (once you install a cache)  1Gb networks are very economical and easy to setup.  While 10Gb networking is now available, most folks find the cost is simply prohibitive.  (In fact, I have not seen any report of anyone even implementing one on this forum.)  Across a 1Gb network, spinners can deliver 90-98% of the performance of an all SSD system. 

 

The Spinup issue can be mitigated by the setting of the spindown delay after the last disk access setting.  You can setup to delay the spindown up to eight hours after the last access.

 

You will get a rough idea of the performance of local networked server files by seeing if the access time from a share between Windows (or Mac) computers is acceptable.  I just ran a quick check of up loading up a 54MB PDF file from my test bed server (drives previously spun up) by double clicking on the file name and it was open into PDF-XChange Viewer in less than 2 seconds.  A 110MB PDF file took a faction longer...  Personally, from what I just determined from this quick test is that mirroring files locally provides little benefit.  However, This statement should be taken with a grain of salt if you are doing things like video editing on files stored on a network.  This is something that I have absolutely no experience in doing. 

Is this VPN speed the proper number?  Because if it is, any unRAID array will support direct writing to the array using any modern spinning hard disk (without the use of a cache--  SSD or cache). I know a lot of folks (Myself included at times) will confuse Mb/s  (megabits per sec)  with MB/s (Megabytes per sec). 

 

As someone who doesn't work with this stuff I do find all the different speed specs confusing but that is the correct speed.

 

 

The Spinup issue can be mitigated by the setting of the spindown delay after the last disk access setting.  You can setup to delay the spindown up to eight hours after the last access.

 

This is where my limited knowledge of hardware kicks in -- I know doing this will cause extra wear and tear on the drives but I don't know what that means in real-world terms -- basically how much would it shorten the life of drives to have them spun-up 14-18 hours a day?

 

1Gb networks are very economical and easy to setup.

 

They are economical but I'm shocked at how even getting a basic question answered has led to contradictory answers from people who both seemed informed -- basically I've been trying to find out if I connect all the devices to a gigabit switch but have some slower devices on a fast hub off by themselves will the entire network decrease to the lowest speed or is all that matters what is between the two devices and using Google I've found people saying both. Luckily I have all the hardware to test this myself so I will tonight. I've always thought that all that matters is what is between the the two devices communicating but started to doubt myself.

 

Although unsupported I’ve been using SSDs on my test server for a while and there were never any unexpected sync errors, trim would almost certainly invalidate parity but Unraid doesn’t allow trim on an SSD that is part of the array, that leaves SSDs internal garbage collection, I purposely tried to provoke it and couldn’t, this does not mean it can’t happen, but there are a few users using at least one SSD as an array drive and never reported any sync errors.

 

In the end I would say that it *should* be safe, but in the beginning you should do frequent parity checks, if there is a single sync error then stop, note that even if there are sync errors you would only lose/corrupt data in the event of a rebuild if one of the SSDs failed.

 

What prompted this was an outside vendor's tech completely trashing the computer that had all the critical files for which there was no backup -- I know irresponsible. So now I'm going the opposite extreme and setting up a rather high level of backups and redoing the entire network plus buying a couple of new computers. I might return to the all SSD array later but maybe I should just use unraid for the big array and look at something else for the small NAS.

This is where my limited knowledge of hardware kicks in -- I know doing this will cause extra wear and tear on the drives but I don't know what that means in real-world terms -- basically how much would it shorten the life of drives to have them spun-up 14-18 hours a day?

It's my understanding that people in the industry feel the longest life is achieved by keeping them always spinning, never powered down or even spun down.

 

1Gb networks are very economical and easy to setup.

 

They are economical but I'm shocked at how even getting a basic question answered has led to contradictory answers from people who both seemed informed -- basically I've been trying to find out if I connect all the devices to a gigabit switch but have some slower devices on a fast hub off by themselves will the entire network decrease to the lowest speed or is all that matters what is between the two devices and using Google I've found people saying both. Luckily I have all the hardware to test this myself so I will tonight. I've always thought that all that matters is what is between the the two devices communicating but started to doubt myself.

It may have been a limitation of some of the earliest gigabit switch models, but not recently.  Each connection is negotiated separately, so you can have a mix of speeds on same switch.

Thank you.

 

Well in that case if there is no issue with ruining the drives 24-7 then I'll just not let them spin down.

 

That was always my impression of how switches worked but it got into my head that I might be wrong and I Googled and the first thing I found was someone who sounded a lot more knowledgeable than myself saying the opposite.

Since your space requirements are so low you could just setup an array with 1 parity and 1 data and get near full speeds since unraid uses a setup like this as raid 1.