# Raid 0 vs Single HDD with Nikon D850



## dkperez (Dec 8, 2017)

Operating System:Windows 10 Pro
Exact Lightroom Version (Help menu > System Info): 7.0.1

My editing computer currently uses a pair of 2TB drives in RAID 0 for holding images.  And it gets backed up daily, and imports get written to a separate backup and all that, so there's no problem with losing data if the array collapses.  They're Hitachi, 7200 rpm drives, so they're reasonably fast.
BUT, though it's been largely trouble-free, I'm curious about how MUCH performance increase I'm actually getting or going to get versus a single 6TB 7200 rpm drive in the real world...  

Not benchmarks or artificial stuff, but when loading and working on an image from my D810 or D850, just how much faster is the RAID likely to be at loading, opening a 100% preview that it has to create, writing changes to the xmp files, etc.

This being the Lightroom forum, I'm using that, but the same question applies to Photoshop...  

If I'm looking at a 3 4, or 5% increase in the real world, I'm thinking a single, large drive makes more sense.  If it's 20,30, 40% then I'll keep the RAID 0 and just put in larger drives as needed...

Thoughts?


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## Linwood Ferguson (Dec 9, 2017)

I think you will find that for lightroom in the vast majority of the circumstances you cannot tell the difference using it for image storage. Now maybe for the preview cache, ACR cache, but the image storage is not used that much. Sequential read speed (e.g. opening an image) on raid-0 vs raid-1 is unlikely to be significant compared to image rendering time, and for such small IO I doubt the actual time is much faster (latency, based on what the disk was doing before, is probably at least as relevant).  This is a guess, of course - to tell you would have to try it.  But it's an educated guess.  If you have a system disk that's non-raid or SSD to test again you can just put individual folders there and see if you can even tell.

From my experience lightroom performance is mostly about the CPU, a bit for disk speed in preview and temp areas and occasionally in catalogs, memory is important but only up to 16g or so, but mostly, almost all the time about the CPU speed.  And with 7.0+ it's about number of cores -- more than 4 is a significant improvement in parallelism (not sure exactly where the breakpoint is, but it's more than 4, and at or less than 8.  Hyperthreading counts in that (which is why I only compared 4 and 8).


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## dkperez (Dec 9, 2017)

Thanks for the response.  My experience (I had to install the latest Lightroom because of buying a D850) so far is that LR Classic hasn't been any faster for me.  In some cases it SEEMS slower, but that may be because with of all the claims of improved performance I'm expecting perceptible improvements and not seeing them.  So, I was rather concerned that if I simplified the system by installing 1 large disk instead of continuing to use RAID 0 I'd see even further performance deterioration.


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## clee01l (Dec 9, 2017)

dkperez said:


> I had to install the latest Lightroom because of buying a D850) so far is that LR Classic hasn't been any faster for me


Some of that "slowness" might be attributed to reading 46mp as opposed to what you could produce with your old camera.  While your post concerns the speed of the "writing" end of the import process, it does not address the "reading" part of the process.  First you may need faster SD/CF cards than what you were using (and getting by with) in your old camera. Next, what is the speed of your card reader?  If you are still at USB2, then you will be at a performance disadvantage until you upgrade the whole system to at least USB3.0. At this point I will admonish you not to use the camera as a card reader even though it has a USB3 connection.  The recommendation here and elsewhere is to buy a dedicated USB3 card reader. 

A little background on the import process: Lightroom uses Working storage (in your case C:\Temp) to stage the imported files.  The more cores available in your CPU (up to 6), the more files that LR can simultaneously pull off of the camera card.  This also means that you need lots of free space on the C:\ drive for temporary files.  Writing original copies out to disk is really a task that happens in the background and not related to the activity that you see happening on your LR import screen. That speed is determined by the availability and size of the disk cache and in the case of RAID, the RAID controller buffer size. Buffers are important because the ability of the operating system to handle data exceeds the capability of the mechanical disk writing properties.


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## Linwood Ferguson (Dec 9, 2017)

@dkperez, I think most people are seeing speed improvements in the building of display (library) previews. Speed improvements were also made elsewhere, with more mixed results. They changed how it interfaces with your GPU (if any), and some found it better, some worse, some no impact (it is always worth trying it with GPU on and off; note GPU still only affects the develop screen interactive work, nothing else). They also changed (with some of it in LR6) how they use parallelism, in preview builds and exports (maybe elsewhere) which helped people with lots of cores.  Also starting in later LR6's they changed how it prepares a develop preview with look-ahead while in develop mode to help going from image to image inside of develop mode; this is a mixed blessing that can help a lot with responsiveness going to the next image, but at the expense of slower response on the current one.  Again, mixed results.

There are probably more things also, but I think the "mixed results" is a fair synopsis, other than preview build time, which does seem pretty universally faster (for a given camera's image size, Cletus' comments are highly relevant if your first LR7 experience is also the first time editing D850 images). 

Definitely not fixed is Lightroom's tendency, for some people, to get slower and slower over time.  If you see that, it's always useful to take a minute to close lightroom, wait the few seconds for it to finish closing background jobs, and restart it.  Some people are lucky and do not notice the slowdown over time; for some it is a huge difference.

But bottom line is Classic was a very welcome release in that Adobe paid attention to performance, but they had a huge hole to dig their way out of, and are still pretty deeply in it.


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## PhilBurton (Dec 9, 2017)

dkperez said:


> Thanks for the response.  My experience (I had to install the latest Lightroom because of buying a D850) so far is that LR Classic hasn't been any faster for me.  In some cases it SEEMS slower, but that may be because with of all the claims of improved performance I'm expecting perceptible improvements and not seeing them.  So, I was rather concerned that if I simplified the system by installing 1 large disk instead of continuing to use RAID 0 I'd see even further performance deterioration.


David,

Victoria has published a guide to Lightroom performance and so has Adobe.  Depending on how much memory is in your system, adding RAM may be a better investment.

Phil Burton


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## LRList001 (Dec 9, 2017)

PhilBurton said:


> David,
> 
> Victoria has published a guide to Lightroom performance and so has Adobe.  Depending on how much memory is in your system, adding RAM may be a better investment.
> 
> Phil Burton



Moving the LR6 catalogue and cache to an ultra fast disk drive does speed it up, scrolling through 1:1 previews reduced to mostly instant.  LR6 doesn't seem to use RAM much above 8GB (although there are plenty of other reasons for fitting extra RAM).


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## tspear (Dec 9, 2017)

I have the catalog and previews on an SSD.
My images are located on two Windows based software mirrored hybrid 3TB disk drives (32MB cache if I recall, mostly affects write performance).
Just because I could, I broke the mirror and deleted the previews folder.
When bringing up the library and scrolling, there was a significant difference in perceived performance between a single disk and the mirror. I had my 13 year old daughter do the scroll test and did not say which configuration was which (she also would not have understood).
When switching into the develop module, neither of us could tell the difference.
After the previews were built, we could not see a difference in the performance between a single disk and the mirror.

The mirror was also faster on my import/copy test from card. I imported just under 64GB of images, and Lr was much more responsive and able to handle browsing images and jump to 1:1 in the library with minimal previews built (I only build minimal preview on import, since I tend to delete a fair amount after importing, and I have not changed my workflow settings since getting newer/faster/better hardware).

Note: This is with a Canon 6D, so roughly half the size in terms of images

Tim


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## Linwood Ferguson (Dec 9, 2017)

tspear said:


> When bringing up the library and scrolling, there was a significant difference in perceived performance between a single disk and the mirror. I had my 13 year old daughter do the scroll test and did not say which configuration was which (she also would not have understood).
> When switching into the develop module, neither of us could tell the difference.


While there are previews built for develop now by the look-ahead process in develop mode (I'm not sure where they are stored -- ACR cache maybe?) the regular LR previews are not used in develop at all, only in library.


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## Jim Wilde (Dec 9, 2017)

Ferguson said:


> (I'm not sure where they are stored -- ACR cache maybe?)



System Cache, I think.


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## Linwood Ferguson (Dec 9, 2017)

Jim Wilde said:


> System Cache, I think.


That's a Mac thing right?  Any idea what it translates to for Windows?


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## clee01l (Dec 9, 2017)

Jim Wilde said:


> System Cache, I think.


Also called Working Storage.


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## Jim Wilde (Dec 9, 2017)

It's the same on both systems, i.e. RAM which may be committed to LR or cached by the OS. When walking through images in Library or Develop I see movement in both committed and cached RAM on both platforms.


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## LouieSherwin (Dec 11, 2017)

David,

I would like to add while RAID 0 (striping only) will improve disk IO speed it comes with a loss of reliability. I don't remember the details of probably theory but it is some thing along the lines the following. If probability of failure of each disk is x then the probability of a two disk RAID 0 system is 2x.

RAID 0 is really intended to maximize IO and is usually used in large realtime data collection systems where massive amounts of data are coming in and need to be stored or lost. Then the collected data is spun off to a reliable but slower backend storage system for analysis. 

You are probably better off using just a bunch of disks (JBOD) to increase your local storage capacity. Lightroom handles using multiple hard drives for image storage quite well. In fact it even gracefully handles them when they are offline. The only trick is that with Windows you need to assign them letters high in the alphabet so that the drive letter doesn't accidentally get stepped on by temporary drive. There have been a number of discussions on the forums recently with people having this problem.

I also tend to shy away from the brand new high capacity latest and greatest of anything. "You can always tell who the pioneer are, they are the ones with all the arrows stuck in to them."  I don't want to spend my time working out someone else's bugs. To that end I am at least a generation or more behind. I am still using 2TB and 3TB drives and am just considering moving up to larger drives.

-louie


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## Linwood Ferguson (Dec 11, 2017)

Jim Wilde said:


> It's the same on both systems, i.e. RAM which may be committed to LR or cached by the OS. When walking through images in Library or Develop I see movement in both committed and cached RAM on both platforms.


Ah, so it is definitely stored in RAM not persisted across restarts.  Thanks.  Was curious if you could observe it in a practical way, try to understand more about what it was doing.


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