15 February 2014

Online Backups Can Kill Internet Speeds

Several months ago, I decided to get an online backup service so I had an offsite backup of all my pictures, files, etc. After a lot of research, I went with Backblaze. They offer unlimited storage and will grab any external drive attached to the computer that isn't a "backup" drive (like a Time Machine partition). At $5 a month, it is also reasonably priced.

Fantastic! I went off without a care. However, without realizing it, I made a small fatal error when setting up the service: use unlimited bandwidth for backups. Little did I know this would cause lots of fun and games as for the last few week I've been trying to diagnose why my internet was suddenly so slow!

Today, I finally figured it out, my Backblaze uploads suddenly got faster. It now saturates my upload bandwidth. For those that understand how networking works no explanation is needed, but suffice it to say, this can easily cause all network activities to grind to a halt. <- that link explains it fairly well. Below is a picture of my degraded situation =)

After determining the issue, I have now throttled my backups to about 25% of my standard bandwidth. Everything is back to normal! However, I still wanted to understand what changed. A little bit of perusing the Backblaze blog revealed something that may be related: recently (past 6 months) they brought online a new data center.  Congratulations! I wonder if their bandwidth has suddenly increased to fill up those disk drives?

12 February 2014

File Access between Windows XP and 7

Windows 7 machines are horrible at accessing Windows XP machines. Removing all permissions, restrictions, security settings, etc doesn't consistently solve the problem.

This has been a problem plaguing me ever since my company was forced to have XP and 7 machines on the same network. Well, a friend of mine found this website that seems to have the solution.

I am copying the major portion of the fix here so that I don't lose it. Hope this helps someone!

After running rsync for a short amount of time, I discovered that I was getting memory allocation errors related to the Windows share.  After unmounting, I attempted to remount the share and received the error:
mount error(12): Cannot allocate memory
Refer to the mount.cifs(8) manual page (e.g.man mount.cifs)
After checking the Event Viewer System log, I found the following error:
Source: srv
Event ID: 2017
Level: Error 
The server was unable to allocate from the system nonpaged pool because the server reached the configured limit for nonpaged pool allocations. 
Some research led me to find this Google Groups discussion about the problem and this Microsoft Technet article discussing the solution (look at the bottom of the page). 
Apparently you need to tell Windows that you want to use the machine as a file server and that it should allocate resources accordingly.  Set the following registry key to ’1′: 
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache 
and set the following registry key to ’3′: