Timing Performance with Windows Media Center

My new Gen3 Drobo seems great for Windows Media Center storage. I would be great to have 8TB of HD video for the server.

In moving video files, the array can sustain 75-80 MB/sec write speeds. More than fast enough for the 2-4MB/sec HD streams.

However, when the array is handling WMC storage, when it has 13MB/sec of traffic to WMC and 15MB/sec of backup traffic, the video playback stutters.

I’ve tried turning on “high performance” write caching, though that makes mounting the drive from an unsafe shutdown a 20 minute penalty.

The Highest Active Time stays between 80 and 100 %. It seems that USB3 DAS has some chokepoints other than just getting the data into the drivs.


Two more parameters, from DroboDashboard:
IOPS to backup program = ~450-520
Read Throughput to backup = 20-24MB/sec

In comparison, for a single HD stream:
IOPS for video = 20-22
Read and Write throughput = 1MB/sec

So I may have understated the backup share of the 28MB/sec stuttering situation in the prior message.

Sure, it would be cool if the backup program had a throughput or priority adjustment, but that means finding a new program. Is the the best performance I should expect?

I recommend to contact the online support Team - Could be that one or more drives are “misbehaving” by slowing the unit down (high response timings).

Also: Check if you have the latest USB / Chipset drivers installed; the USB buffering during R/W operations could be the cause too.

and support team might ask for drobo diagnostics too :slight_smile:

I’ve come to accept that 20-24B/sec write may be all I should expect.

I’ve come upon a new problem. When my Media Center has to reboot, it takes 15 minutes for the Drobo to mount. I’m not talking about a power failure, I have a UPS. I’m talking about a safe shutdown via Windows followed by a restart. I can’t even get the Drobo program to open during this time.

I have three potential theories, and I’m looking for a recommendation:

  1. I shouldn’t have set “high performance” write caching in Windows, because that causes some fsck (or the Windows equivalent) on a reboot.

  2. The problem is Windows Backup/Restore, for which I have a separate Backup partition set up. The Knowledge Base hints this at http://support.drobo.com/app/answers/detail/a_id/163 , though I thought the whole purpose of the new “backup partition” feature was to make this sort of thing work.

  3. The Drobo is doing something that takes forever. This isn’t indicated on the LEDs, all are solid green and there is about the space I’m expecting.

It just takes a long time to do any sort of experiment, and most of the time there aren’t any symptoms.

hi just a question… how big is the volume size?

It is Gen3 Drobo with 4 Seagate NAS 3TB drives. 5 blue LEDs full. As you know, there is no “off” command for WMC. As a result, I can’t dismount the drive with the Drobo application because it’s always still in use. When I shutdown the system, waiting until the Drobo power LED is yellow, and then restart it the Drobo does not mount or respond to the Drobo appplication for 17 minutes.

17 mins is long enough that WMC has given up waiting for the device to mount, and purged it from the list of storage locations. When it finally comes online, recordings are impacted for another 4-5 minutes while WMC reads all the file statis back in to rebuild its directory.

What’s the Drobo doing, and why doesn’t the filesystem show as clean after a reboot? Should I reformat the Drobo as all “backup” volume, so that the Windows file system is used rather than the Drobo one? This seems like a huge step backwards, but this device isn’t really working in the WMC application.


hi thanks for more info,

when you have a moment, if you can see the drobos drive letter in My Computer ,can you let me know what does the max size show? that is the actual volume size that i was wondering about.

for your newest issue maybe there is a way to shut down wmc, just before powering down computer and drobo but it might be useful if you can get Process Explorer and to run it as admin and search for the Drive Letter of your drobo under search for dll/handle button. maybe some details can be found there?

that will show a list of programs which are currently locking/accessing the drobo.
some are windows related, such as recycling bin etc, but sometimes when im unable to shutdown a drobo via dashboard, i run it and find a hanging handle/process which i can then close and it shuts down.

I used to run XP Media Center and I’m almost sure it had a shutdown to it? Has that really been removed in newer versions of Media Center?