Xpenology (Synology) fast read speeds slow write speeds

Question

For 2 years I've used a Xpenology server which has an Raid 0 volume and works perfectly fine. Gigabit read and write whitout any problems.

Now am I installing a Raid 5 volume 3x4 tb WD red. I'm not sure why but the read speeds are te same full gigibit speeds, but the write speed start at a full gigabit and drops after a few seconds.

What can I do about this? All the info I found gave tips for faster inital installs, but not for this issue. Can this be a buffer issue?

Answer 1

After some more research and try and error I've found some tips. First of all it seems a raid 5 works faster if there're more disks available. For the test I used 3 harddisk and now I'm building a raid 5 with 4 harddisks which will hopefully be faster. A friend of mine has a 5 disk raid 5 setup and is much faster then the 3 disk raid 5 of mine.

also this website was very helpfull. Yes it is all about the rebuild, but I've changed the settings after the build and the raid started to speed up. However I didn't turn de NCQ off.