Hi there,

 

I have read here: http://www.lime-technology.com/wiki/index.php?title=FAQ

that unRAID performance (assuming gigabit networking) is about 22MB/s and 40MB/s for reads and between 8MB/s and 15MB/s for writes.

 

Is that true? I am building this system:

http://lime-technology.com/forum/index.php?topic=4660.0

for unRAID and really hope it can do more. My Qnap TS-509 is doing about 70-80MB/s

 

Thanks much and greetings

If raw performance is a key requirement, unRAID is not likely to be the best solution.

 

Personally  the most important benefit offered by unRAID is that if the array fails, the individual drives are still accessible, unlike traditional RAID arrays.  The ability to pull out a disk and read it on any Linux box brings significant peace of mind.

 

In traditional RAID if two disks fails, your likely to lose everything in the array, while with unRAID you'll only lose the contents of the two disks, and will be lost.

Note this is no implying any form of RAID is a substitute for backup!!!

 

Recovering from an unRAID multiple disk failure is also significantly faster as only data on the lost disks needs to be recovered, and the rest of the disks can still be used.

 

Some more comparisons can be found in:

http://www.lime-technology.com/wiki/index.php?title=FAQ#What_are_the_advantages_of_unRAID_over_similar_products.3F

http://www.lime-technology.com/wiki/index.php?title=FAQ#What_are_the_disadvantages_of_unRAID_compared_to_similar_products.3F

Also, expansion of the array is faster, easier and safer.

 

When you expand the array, you are expanding to the full size of a single disk.

Your prior data is untouched. If the addition to the array fails before use, the rest of your precious data is safe.

You can expand the array as needed with the most cost effective drives at the time of growth.

Expanding/Replacing current drives is also very easy too.

I have read here: http://www.lime-technology.com/wiki/index.php?title=FAQ

that unRAID performance (assuming gigabit networking) is about 22MB/s and 40MB/s for reads and between 8MB/s and 15MB/s for writes.

 

Is that true? I am building this system:

http://lime-technology.com/forum/index.php?topic=4660.0

for unRAID and really hope it can do more. My Qnap TS-509 is doing about 70-80MB/s

 

The numbers in the FAQ are based on average 'real work' figures, across a network, with ordinary hardware.  I don't doubt that some unRAID users can read over 100MB/s locally, but these numbers better represent Real World situations, where the network and busses and the speed of source and destination drives are factored in.

 

The figures for writes are based on unRAID releases prior to the current release of v4.5-beta8.  This new release is reported to essentially double the speed of writing to parity protected drives.  At some point, the FAQ will be updated to reflect that.

 

I am curious to know how those Qnap figures were measured, and what OS and drive were used on the second machine.

Thanks guys, for the posts.

 

Rob, the client was a Mac OS X Leopard writing to a non-OS/dedicated 3.5" Seagate 7200 SATA attached disk. Gigabit switches were managed enterprise class HP ProCurve GigE. I think that the NIC controller in the Mac is an Intel NIC, they perform really well. Transferring huge files.

 

I am building a Norco 4220 well balanced PCI-e system and really would like the server to be on the GigE max-performance side of things. Not messing with shared 32bit PCI cards, etc. Everything else about unRAID I pretty much like and it is not intended to replace my other RAID5 array. I am aware about the diff between traditional RAID arrays and unRAID/FlexRAID/disParity systems.

 

Any read/write performance numbers with the current v4.5-beta8? 7200 NCQ Seagate 1.5TB drives, 15-20 of them incl. parity and cache on a Supermicro mobo with Inteil NIC... just a maxed out config?!