Hardware Sizing Backup Server

[pronto]

Hi Community,

 

we have to reconfigure our backup strategy because we ran into a couple of troubles with our current setup. We decided to purchase two new servers for file- and backup-server storage. Are there any recommendations available how to size the server hardware for Retrospect Multiserver on Windows connected with 1 GB/s LAN Interface? Currently we have to backup round about 4 TB data for a full backup, running from Saturday to Sunday each weekend and should be completed within by 24 hours. This needs to backup round about 2,8 GB per minute and for Retrospect this is quite a lot. I never saw this transfer rate from server to server using Retrospect but maybe it is possible in some way. 2,8 GB per minute is round about 40 % of a Gigabit LAN (~390 Mbit/s). Possible?

 

Thx & Bye Tom

[Lennart_T]

"That depends".

 

If your contents consists of a gazillion of tiny files adding up to 4 TB, I would say "no".

If you have less than a million files, I say it's possible. 

 

On our seven years old hardware, we get around 1.5 GB/minute going from a NAS to a SCSI LTO 3 tape drive.

[pronto]

"That depends".

 

If your contents consists of a gazillion of tiny files adding up to 4 TB, I would say "no".

If you have less than a million files, I say it's possible. 

 

On our seven years old hardware, we get around 1.5 GB/minute going from a NAS to a SCSI LTO 3 tape drive.

 

Yes the size and number of files differs from minimum size 4KB up to a gigabyte or more and I guess the total number of files is more than a million. It seems that you backup your data directly on tape? We backup our data on a RAID subsystem and once a week we transfer the disk backup sets to tape up to 6 GB per minute using a LTO 5 tape library. This is pretty fast but not my problem yet. Now we backup data with less than a GB per minute and so far increasing the backup speed up to 1,5 GB per minute would help quite a lot and is better than nothing. The problem is how long I can work with this setup because I have to explain the invest of about 10.000.- Euro for both servers.

 

Thx & Bye Tom

[Lennart_T]

Sorry I wasn't clear. The backups from the "clients" (in Retrospect parlance) are stored on disk media sets on our (old) NAS devices. Then we do a transfer from the disk media set to the tape media set.

 

How much more than a million files? Two million? Ten million? 50 million?

[pronto]

Sorry I wasn't clear. The backups from the "clients" (in Retrospect parlance) are stored on disk media sets on our (old) NAS devices. Then we do a transfer from the disk media set to the tape media set.

 

How much more than a million files? Two million? Ten million? 50 million?

 

Okay currently the fileserver stores exactly 1.067.711 files in 238.007 folders with a total size of 2,6 TB. This is the server who would become replaced too. Additionaly there are 4 more servers to backup with a total size of less than a TB, this are databases using the Exchange and SQL server agent or domain controllers. This backups are running independend from the fileserver backup but at the moment these backups are overlaping with the fileserver backup.

 

Thx & Bye Tom

[jotrago]

Hi Tom,

 

Interesting setup you have there.

Lets do a few sums with what you have given us.

Full Backup of 4TB in 24 Hours requires ~2.8 GB / min as you say. That's high but may be doable.

Your File Server is 2.6 TB with ~1Mill files that means your average file size is around 2.4MB which is quite large. Maybe you are a Media  house or similar whihc have larger file sizes.

Thus the balance of your backups are ~1.4TB (Exchange, SQL, AD)

 

In my experience a typical general purpose file server has an average file size of around 500KB. Typically the bigger the files the faster they backup (AND Retrospect 9 now has support for Block level incremental backups of files over 100MB in size)

 

Is your Raid Backup Target Directly attached to the Backup Server (SCSI/SAS/FC)? or is it a NAS device.

 

Retrospect can run multiple backups in parallel, up to 8 for Multi Server, provided each backup has a different destination backupset, (No Problem with Disk Backup)

With some clever arranging you could have separate, parallel jobs for Exchange, SQL, AD, & File Server Data. If the File Server has separate volumes on separate disks/arrays/Luns/Volumes you could break that up into multiple jobs.

With Three source servers running you may manage to flood a single GigE Nic, you might want to consider Multiple GigE Nics / Teaming / 10GigE (if your switch supports these) for the client side connections.

If you backup Target Raid is a NAS then get that on a dedicated Teamed/Trunked/10GigE Dedicated Link.

 

Given that most modern servers have multiple (up to 4) Nic Ports built in,  I am also a fan of creating a separate Dedicated Backup LAN (DataCente Backup LAN) between the Backup Server, File Server, Exchange & SQL servers etc. Decent GigE Switches are so cheap this shoud be a no brainer, and Retrospect has elegant support for multiple nics.

Modern Servers are so Powerful they can often sustain a GigE backup running on a dedicated Nic, during production time without affecting users, this can extend your backup windows.

Retrospect can make good use of up to 2GB of RAM  over and above the requirements of the OS, and anything else running on the Backup Server (hopefully not much)

Remember that Retrospect writing to the Windows Temp File, Catalog File, and Backup Set Files are very intensive. These files should be on separate spindles / Luns / Arrays.

Avoid Built in / On Board (Fake) raid contorllers. They are AWFUL. If you are buying new hardware anyway, fork out the $ for proper Hardware Raid Controllers.

You wantt each of these 3 files systems to capable of 120MB/s Plus.

Enable Checksum Verification and DISABLE verification during Backup. (This can Halve your backup time if you were doing full Verification) Then run separate Verify Jobs during the Day, without impacting the servers.

 

Let me know if I can be of further help