Hi Uroni,
we are using urbackup from past one and half year. Its really a great product.
We are running 4 backup servers for almost 100 clients. Our backup process works very slow due to Network and HDD I/O issues.
Now we are going to procure NAS with 20 TB with RAID6. we planned to attach iSCASI drives to all the servers to add the storage.
Also we are going to change the switches to 1gig
Is it helps to improve the performance of my backup cycle.
Perhaps before Uroni gets to aswer your question the following reading could help broaden your aproach and understanding of the problem:
https://www.urbackup.org/administration_manual.html#x1-9800011.6
It is about the file system type on the backup server. It seams it is not without significance to the overall performance of the backups taken.
regards,
Lin
We are having the same sort of discussion internally now as well. Basically deciding between iSCSI and direct attached SAS. Likely we’d use ZFS in either implementation (per the documentation Lin notes above).
Also linforpros, I don’t know what your network architecture is like that necessitates 4 backup servers. Have you considered perhaps having one backup server with direct attached storage and then bonded multiple 1Gb ethernet to service your clients? From what I can tell in reviewing the documentation strategic use of a few SSDs for temporary file buffers and/or in conjunction with a ZFS SLOG.
ssemone, it is gurajalarahul who started the thread and it is his network topology you are referring to. I share your view on that, though.
Lin
Thanks for your inputs.
Until now we do not have any storage solutions in place. So we want to centralise it for making tapes and disaster recovery.
I have a data where each full backup cycle goes to at least 150GB.
would you please give some useful inputs on our plan.
I would think some good questions to ask which could inform an answer would be:
How many clients do you have?
How much initial data do you have?
What is the rate of change in your data (mostly office productivity files or is there lots of big research data)?
How much data might be deduplicated (e.g. are you backing up full drives of the same machines)?
How compressible is your data (e.g. text vs video)?
How long do you need to keep (retain) the data?
Do you need both disk image and file backups?
Do you need off-site storage?
What is your network topology like? (gigabit ethernet? mostly remote clients over the internet?)
With all of those answered I’d imagine you could come up with a pretty good sense of what kind of system you would want to put into place.
I hope that is helpful! 
I am sorry, I was offline for some days. Please find the following:
How many clients do you have?
Ans: Nearly 100 clients
How much initial data do you have?
Ans: Around 300 GB
What is the rate of change in your data (mostly office productivity files or is there lots of big research data)?
Ans: Around 150 GB
How much data might be deduplicated (e.g. are you backing up full drives of the same machines)?
Ans: I donth think there is much dedulicated data
How compressible is your data (e.g. text vs video)?
Ans: we do have only ms office files and outlook PST
How long do you need to keep (retain) the data?
Ans: As we are looking for keeping around 1 year. But in disk it would be around 45 days and later we write it on Tapes
Do you need both disk image and file backups?
Ans: At present we do only Full and Incremental file backups
Do you need off-site storage?
Ans: Yes, but we manage with Tapes
What is your network topology like?
Ans: 1 Gig
I’m making the assumption here that we are talking about ~ 30GB per client with ~ 15GB per client per year. So approx 450GB/year. So lets go ahead and say 1TB per yer. 
Given that you are going to retain for 45 days on disk you have a lot of options. It sounds like you wouldn’t need to plan for more than 4TB of raw storage over a 4 year life-cycle on a device.
Given that there are any number of devices you might purchase to meet that need here’s an idea of what might work. (note that I have no relationship with this company, they just have an easy interface for configuring servers).
The configuration below paired with Ubuntu and ZFS (which can take advantage of the SSDs for caching) is at least a good place to start. Note that UrBackup can also take advantage of storing temp files on an SSD.
Hope this helps!
https://www.abmx.com/1u-rack-mountable
U Rackmount Server - 8 Hot-Swap Bays $4,398.88 /ea
Black color
Supermicro® X11SSL-CF Motherboard
4-Core 3.50 GHz – 8MB Cache, 8 CPU Threads – Intel Xeon E3-1240V5
64GB (4 x 16GB) – DDR4 2133MHz ECC Un-buffered Memory
256GB SSD - SATA 6.0Gb/s - Endurance: 150 TB Written – Samsung 850 PRO
256GB SSD - SATA 6.0Gb/s - Endurance: 150 TB Written – Samsung 850 PRO
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
1.0 TB HDD - SATA 6.0Gb/s, 1.4M hrs MTBF – Seagate® Enterprise, 2.5-inch
No Additional Card Selected
Front USB 2-port Adapter
No SATA DOM for boot
Redundant Power Supply (Adds Acoustic Noise)
Rackmount Mounting Kit and Rails (Included)
Linux