Using NAS as Sage's main storage

[srothwell]

Is anyone using a NAS as Sage's main storage?

I'm looking to buy a Synology DS413 NAS Unit. I seems perfect for nearly everything in my home. And, I'd like to remove the SATA hard drives (4 of them) Sage is using in the PC and have Sage use the NAS

Obviously the NAS will only communicate via Gig-E. I have 5 tuners.... 3x HDHR and 2x HDPVR.

Before I plunk down $$$$ anyone have anything like this successfully working and do you think there'll be any issues with that many tuners? I also have 45 places that can watch sage at the same time, although usually no more than 2-3 ever do.

Thanks for any advice.

[Evil_Attorney]

Yes. I'm using a Synology DS1511+ over a gigabit network with 7200 rpm drives and no problems. I can simultaneously record two shows with my HDPVRs and stream a blu-ray.

I would hesitate to have this kind of setup with other brands of NASs. For example, Drobo has a reputation for being somewhat on the slow side. But Synology makes excellent products and is constantly improving their software. Just make sure your network is up to the challenge (e.g., gigabit switches/routers and at least cat5e cables).

[srothwell]

Originally Posted by Evil_Attorney

Yes. I'm using a Synology DS1511+ over a gigabit network with 7200 rpm drives and no problems. I can simultaneously record two shows with my HDPVRs and stream a blu-ray.

I would hesitate to have this kind of setup with other brands of NASs. For example, Drobo has a reputation for being somewhat on the slow side. But Synology makes excellent products and is constantly improving their software. Just make sure your network is up to the challenge (e.g., gigabit switches/routers and at least cat5e cables).

Thanks. I know the 413 isn't quite as sophisticated as the 15xx series, but I'm going to experiment first and see how it goes. I know my house has some cat 5 cable in the walls, but the good news is the NAS will be right next to the sage server PC on a common switch (that doesn't go through the walls) so all should be fine.

thanks for the input.

[Evil_Attorney]

To be fair, you could run into issues if all tuners were recording and you had more than 3 people watching shows, especially if they are watching one or more blu-rays. Sage basically acts as an intermediary between the nas and the clients. So a live TV show enters the Sage server, is then passed to NAS, is passed back to the Sage server, then sent to the client. You might want to do some rough, back of the napkin calculations based on this to ensure that under your relatively heavy usage you wouldn't be running into any issues.

[PosterBoy]

It would help mitigate the problem if you have 2 GigE connections on the Sage Server (and a managed switch that supports it) and can aggregate the connections.

As for the raid setup you use (assuming you are using raid), do a lot of research to understand the trade offs. I recently added a DS1512+ to my system and was surprised that Raid 10 was definitely the way to go for me.

Here is a really good article on why Raid 5 may not be the best choice.
http://www.standalone-sysadmin.com/b...praise-raid-5/

As far as GigE on Cat 5 cabling, I was also surprised to see that many current switches are speced to run GigE just fine on Cat 5.
for example,

http://www.dlink.com/us/en/home-solu...desktop-switch

100BASE-TX, 1000BASE-T:
UTP CAT 5/5e (100 m max.)
EIA/TIA-568 100-ohm STP (100 m max.)

[Evil_Attorney]

PosterBoy, thanks for that Raid 5 article. I hadn't really thought about the URE issue before. I'm currently using my NAS with Synology's SHR format, which appears to be a modified version of Raid 5, with 2 4tb drives and 3 2tb drives (I have lots of lossless music, ripped blu-rays, and recorded shows). So I am probably extra susceptible to URE issues. I do back up all of the important stuff, so I'm not too worried about catastrophic failure.

I am curious about whether Synology's OS has any type of mechanism to detect and compensate for those types of single bit errors. For example, if you get a single corrupt 1/0 on one of your drives, and that messes up the parity for the corresponding 1/0 on all of the other drives, can the OS look at the file the bit is part of in the file system and correct it by some type of checksum?

It looks like my Synology is set up with an Ext4 file system. So what are the odds of a bit flip not being correctable by the Ext4's checksum?

[PosterBoy]

That is the insidious part of this issue. It is below the level of the ext4 file system. The error is unrecoverable, so the drive flags it as a bad read. The raid software sees the the bad read and because it needs to do its parity calculation, it can't, so it flags the whole array as bad. Wave goodbye to your whole array.

There is some argument in the comments section as to exactly what happens, but apparently, a raid 10 array just copies the bad data and doesn't flag the whole array as bad. From there it is up to the filesystem or whatever other protection schemes are in place to catch it. Worst case a single file is corrupted.

In addition to this issue, Raid 5, and even more so Raid 6 (Synology's SHR-2 is a hybrid raid 6) suffer from write performance issues, CPU loading issues, and IOP rate issues. Raid 10 seems to be a better way to go at this point. Other solutions seem to work as well. ZFS and unRaid solutions appear to be fairly robust even with large disks but these are not an option at this point on Synology boxes

[Oddity]

I have used a readynas nvx for some time now. I use the readynas' iSCSI functionality to map a drive on my sage server.
No issues to date and the readynas' are rock steady.

[Evil_Attorney]

Originally Posted by PosterBoy

That is the insidious part of this issue.

That's exactly the right word for it. I wish I knew about this when I first set up my NAS. Converting my NAS to a RAID 10 setup would be difficult at this point (I don't have room for all my data on other drives). It sounds like my best option is to regularly "scrub" the discs to catch any parity problems and ensure the important stuff is being backed up properly.

[Dargason]

Is stuff recorded from television and ripped from your blue-rays really worth all this trouble and expense?

[Evil_Attorney]

The recorded TV isn't, which is why it isn't backed up from the NAS. However, everything else certainly is. For example, my pictures and home video, including the raw data of everything from Aperture is invaluable to me. I still buy music CDs and have all my music in a lossless format, which would take many weeks or even months to re-rip. Same goes for the blu-rays. Time is money.

[dcardellini]

There are other solutions available if you get the NAS and have problems with simultaneous recording off tuners and viewing.

I record everything to a local hard drive on my Sage Server. I have a batch file that then runs at 4:00 am daily that transfers the entire recording directory to the NAS (as just another Sage recording directory). No problem recording seven HD streams simultaneously and watching a number of these. This has run 24/7 for past five years without a hiccup.

Never a problem with Sage getting confused about these recordings (I do nothing special such as stop Sage and then restart.....I just simply transfer while Sage is still running. If a recording is occurring while the batch transfer takes place, the file is not moved, and everything works great.

...and my local (recording) hard drive is just another partition of my system disk (and is a slow WD Green).

[srothwell]

I will probably just keep the local storage inside the sage PC for a while. I have already started testing the NAS by putting all the movies, music and photos on the NAS, which has opened up much more space on the sage server.

[ProNoob]

Just adding second reference for the setup dcardellini described. I have a ReadyNAS Ultra 6 Pro based setup. The only difference is my batch job runs at 3:00am The setup has worked flawlessly since I set it up nearly two years ago.

[Evil_Attorney]

Are you guys moving the files from one recording directory to another or to an import directory? If the former, how do you prioritize the local directory to do the initial recording?

[ProNoob]

I have two recording directories setup. Let's call one source and the other destination. Each night the batch job copies all files older than 24 hours from the source to the destination. The disk space usage rules on the two directories is setup as follows:

Source - Use all Diskspace
Destination - Use Only 1.0 GB.

This way SageTV only writes to the source directory because the destination is always over 1.0 GB.

Source - is a 1.5 GB drive in my SageTV server.
Destination - is the ReadyNAS with ~9 TB available.

If you have any other questions please feel free to ask!

[nyplayer]

Originally Posted by ProNoob

I have two recording directories setup. Let's call one source and the other destination. Each night the batch job copies all files older than 24 hours from the source to the destination. The disk space usage rules on the two directories is setup as follows:

Source - Use all Diskspace
Destination - Use Only 1.0 GB.

This way SageTV only writes to the source directory because the destination is always over 1.0 GB.

Source - is a 1.5 GB drive in my SageTV server.
Destination - is the ReadyNAS with ~9 TB available.

If you have any other questions please feel free to ask!

What type of tuners do you have. To only use 1.5 GB recording drive. I would fill that up in 1 Half hour HD recording?

[ProNoob]

I'm sorry. I meant a 1.5 TB drive in the SageTV server

I use a Hauppauge HVR 2250 to record HD OTA tv. We dumped cable when we setup SageTV and have never looked back. We have SageTV, Netflix, & Hulu Plus.

http://www.hauppauge.com/site/produc...a_hvr2250.html

[Evil_Attorney]

Originally Posted by ProNoob

This way SageTV only writes to the source directory because the destination is always over 1.0 GB.

!

Wouldn't this cause Sage to delete the low priority recordings on the destination?

[nyplayer]

Originally Posted by Evil_Attorney

Wouldn't this cause Sage to delete the low priority recordings on the destination?

I agree with this the only way it would not delete them if they are marked as manual record.... after moving them.