I have 10 disks and I set up 2 volumes using Raid 5
so each volume has 5 disks allocated

Now Vol1 and Vol2
But we have only one raid controller card

will I face degradation in performance because I have a single raid controller card
I do understand that this is a single point of failure (having a single controller card)
but will my performance be significantly better if I have two controller cards
compared to single controller card

Performance *may* be better with separate controllers for each array depending on how much simultaneous access is involved. It also depends on the controller in use and the rest of the system as well.

'Significantly' is the operative word here, and NyteOwl hit it on the head. However...RAID5 does offer a pretty good amount of safety, but the tradeoff is access speed. I've only had one problem with RAID 5 in my life, and it was because of a bad chassis/circumstance. Others have been painless...bad disk? No worries...swap it out on the fly, and keep going.

But if you're worried, two controllers would speed things up. But before you do it, run some real-world tests...if your applications and users aren't having problems, there's no real benefit to doing it.

Pretty good sounding controller card to handle 10 disks.

Some lower/mid end SAS RAID controllers can handle 32-64 physical devices. What performance would be like with that many connected I wouldn't care to speculate