My questions are :
Q1: Is it better to install it on the VEEAM server ?
Q2: It is said in the document that it will install a named (VEEAM) instance, i see in the services an already Sql server (VEEAM) instance so will it be the same instance ?
because i didn't want to crash veeam
1. Yes, you can install it on the same server that hosts Veeam B&R, but if you use a local backup proxy I would recommend deploying these products on different servers for better backup/replication job performance.
2. Yes, it will re-use already installed instance.
I currently have Veeam Backup & Replication V5 installed on a dedicated VM and its using SQL Express, which all works fine.
I'd like to have some better monitor/reporting and capacity planning facility for my environment so I was looking at the free edition of Veeam One. My question though, can I install these on the same VM as my existing Veeam Backup & Replication install, and if so would this impact anything such as the SQL express install which is currently VEEAM, as I noticed Monitor wants to use this too?
Yes, definitely! But please be aware that SQL Server 2005 which is shipped together with Veeam B&R v6 has 4 GBs maximum size for its database, it might not be enough for your infrastructure (depends on the number of VMs, hosts and datastores).
On a side note, we are going to release a new version of Veeam ONE v6 VERY soon, so I would suggest waiting for this version and then deploy it on a standalone server while hosting Veeam ONE database on a SQL Server 2008 Express, which has a 10 GBs of database max size.