On Wed, 09 Mar 2016 20:49:19 -0500, Paul wrote:

Charlie Hoffpauir wrote:
When I set up Storage Spaces in my Win 10 system for data, I chose
two-way mirror, using 2 physical drives, because I wanted "resiliency"
(I wanted data redundancy in case of a drive failure). That seems to
work fine. But now that I've learned a bit more about storage spaces,
I'm wondering if maybe "read" performance would be improved if more
than 2 physical drives were used. The thinking is that if the data
were spread across 3 instead of 2, reads might be 50% faster? Is this
the case? Is it by default, or must one configure the storage spaces
to use 3 columns instead of two at initial installation to get the
higher peformance? (I'm not referring to using 3 drives to get a
parity effect..... I don't need that big a hit on write performance)
I'm guessing that if I simply add another drive to my existing setup,
I woudln't see any increased read performance...... is that also
correct? One last question... since the Storage Spaces interface
doesn't seem to allow for specifying the number of columns and since
the articles I've read state that this must be done with powershell,
can anyone tell me the Powershell command that would do this?

I've not mentioned Simple Storage spaces, but the MS docs I've read
states that adding more drives does directly increase read
performance... but I'm not willing to give up the data redundancy.
Also, I'm not really needing 3-way mirror.

There's a FAQ here, with some powershell commands in it.

https://blogs.msdn.microsoft.com/b8/...nd-efficiency/

I assume you'd get a bandwidth improvement from using
2-way mirror and using four disks instead of two. But
my attempts to experiment (in a virtual machine), failed.
The Storage Spaces pool formed OK, but I wasn't able
to control VirtualBox in an appropriate way to make
measurements. (I wanted to limit the bandwidth of
each virtual disk, so I could watch them "adding
together". Didn't work worth a damn.) The results
were "all over the place" and a waste of time.

And I don't have enough disks to do real, physical
experiments.

Paul


One of the MS FAQs I read talked about linear increasing read
performance as disks were added to the Simple Storage Spaces (no
mirror, basically JBOD. 2 disks 2x read speed of 1 disk, 3 disks 3x
speed, etc. But when it came to mirror, I didn't see it explained.
They went into loss of write speed (drastic loss) if parity was
included, ie 2-way mirror with parity using 3 drives.... but it just
seemed that there should be some read performance improvement if 3
columns could be set up instead of 2 with 2-way mirror. I don't think
I have room in my SATA ports to go to 4 drives, since I need an
external SATA occasionally and I have an optical drive, and an SSD for
OS and programs.

Maybe I'll just try to set up a small test using small drives and see
what I find. I have four oldish 500GB drives that I could use and see
what happens.

Thanks for the link to the PS commands.