After my last experience with a HD in the TivoHD becoming unusable, and getting help here on the forum, here is my set of recommendations how to deal with these type of issues in the future. While there is a lot of help on the forums, its about a lot of stuff, but not necessarily about only "how should i prepare myself for, and deal with disk failure". So maybe it would make sense to have another sticky thread about this. So here's what my insight is. Not all of it may even be correct or good recommendations. Thoughts / feedback welcome.
1. The problem is almost always the disk
The most common thing to fail in a Tivo is the hard disk. The only reason to look for some other error first is because it may be on your way to getting hold of the disk. Like opening up your Tivo, checking if theree is a bloated capacitor, and most likely there is not, so you directly continue to get to the disk.
2. Recovering a bad disk may likely not work but you can try
When a disk fails, you sometimes can recover from this without a backup, but do not bet on it. My disk failed, resulting in my Tivo hanging in the first welcome screen. I attached it to a linux PC and it was not recognized there either. The forum recommended me to try putting it in a freezer for a few hour and try again. This actually worked.
There is a linux tool called ddrescue that will copy a disk to another disk, skipping bad blocks. When the disk warms up again it may fail again. You free again, and restart ddrescue, it will continue where it left off. Do not try to use dd_rescue, it does not have this restart capability. You want to use SATA or USB3.0 to copy fast because once a disk has started to fail it can go downhill quickly.
In my case, ddrescue managed to copy the whole disk supposedly without any unreadable sector (freezing three times), but Tivo would not boot afterwards from the copy. Using WinMFS or MFSlife the error was MFS file system error. So i assume there was some error writing sectors that did mess up the file systems beyond recovery when the drive was in the Tivo.
3. Recognizing a bad disk may work or not
There are some easy signs of disks giving up, like pixelation, but you can not always expect to get such a warning. My disk just died some time without a visibile warning upfront. You could try to regularily run a SMART check on the drive, eg: via smartmontools from Linux, but on my drive that did not look really bad either. The drive was only running for 2 years, although it was 5 years old.
If you do use any SMART tools, its best to store the results regularily to be able to compare and recognize faster deterioration. It likely also makes sense to regularily run a selftest. But without some additional prep it is of course way to annoying to remove the drive regularily from the Tivo to do this.
4. Pull down recordings with Tivo Desktop or similar tools
The safest place for your recordings is not on a Tivo disk, but on another disk, NAS or PC. The Tivo disk is encrypted with a Tivo device specific key, so it can not be reused on another Tivo. And it can not be part of a raid or automated backup.
In addition, once you pull recordings off the Tivo you can re-encode the HD recordings to a lower bitrate without loosing a lot of quality. I for once think 720p at 1.5Mbps h264 is fine, but the MSOs usually have much higher bitrates because they do realtime encoding and that does not optimize fully for VBR in the content. And of course there is the 1080p quality expectations by customers.
The content you can not pull off the Tivo is the one the MSO has marked with do not copy bit in the stream. This differs quite a bit by MSO or even by market. Suposedly, the FTA channels should not have the bit set, and in my market it is not set for the digital starter package, so that is all i subscribe to. Especially because i often only get to watch series after a season is complete. The rest i get later from Hulu/Netflix. Ok, i have to shut up friends/colleagues to talk about the latest HBO season. So be it. Your mileage may vary, but if you intend to long-term store expensive premium content on your Tivo disk you should not only be worried about disk backup but also the life expectancy of that Tivo.
5. Do backup
With all the issues explained, the i think most important thing is to have a backup strategy for your Tivo drive. Here are some recommendations:
5.1 Your original drive.
Just keep the original drive running long enough until it is updated to the latest version of the Tivo, 11.0k on the Tivo3/HD supports hard disks of up to 2TB. Prior versions of the software only supported smaller disks. When you later copy/resize/upgrade your hard disk you can not go directly to 2TB unless the Tivo image has at least this release.
Try to avoid putting a lot of season passes or the like onto the original disk that will be invalid in a few years.
Once the drive is up to this state, pull it from the Tivo and make a backup. Its sufficient to make just the truncated backup (no recordings), because that is what you want to restore from anyhow.
Once you are done doing the backup, put the original drive in a safe location and never use it again except i emergencies. Like when you are not sure if you have messed up something or whether the Tivo is broken in HW. Then just check whether it still works with the original drive.
5.2 Your work drive
Get a 2TB drive. Do not bother with multiple/external drives drives. Chaining two drives together just makes backup and hard disk replacement so much more difficult.
Restore your original disk backup, resize to the full 2TB and use this drive as your production drive.
The drive expansion sticky thread explains everything about it
5.3 Setup your tivo for backup
You want likely to do periodically do three type of maintenance actions on your operating drive:
A) Full backup when you have recordings on it that you want to survive the unexpected disk death (like from premium channels).
B) Truncated backups when your season passes have changed and you do not want to re-enter all new season passes manually.
C) SMART stats of the drive to get some idea whether to retire a drive proactively or start copying out more recordings that should survive drive death.
Physically unattaching/attaching (cables) the Tivo and opening it to get to the drive to do these operations is cumbersome and did stop me in the past to do these things regularly (eg: twice a year or so). I now set it up so that i do not have to do this anymore:
| Original SATA cable
eSATA PC Bracket | | SATA-eSATA-cable from 2nd SATA connector
cable, bracket | | on Tivo motherboard (for second disk)
removed | |
-----eSATA-connector2 ------eSATA-connector(original) ------ TIVO
eSATAconnector eSATAconnector Backplate
Basically, put a hole for a second eSATA connector into the back of the Tivo, beside the first one for the eSATA drive. buy a SATA coupler and a PC eSATA PC bracket and an eSATA cable. Cable up according to diagram. In result, the connection from the Tivo motherboard primary SATA connector to the internal hard disk is now being passed through the external eSATA cable as a looppack cable.
Now you can close the Tivo and only ever open it up again when you really need to replace a broken internal disk. But you do not need to open it for the following options:
a) connect the Tivo internal HD to an external PC to make full or truncated backup or look at SMART stats.
b) Connect a backup drive to the Tivo to run the Tivo from that drive.
This whole setup makes most sense when you have some PC, like a HTPC in eSATA vicinity of the Tivo so that you do not even have to move the Tivo. eSATA can be up to 2 meters long, so if you do have an HTPC in the same living room setup as the Tivo, this setup should allow you to minimize the effort for backup: No need to disconnect any cables, move or open the Tivo.
Except that i would recommend as stated above, to shut down the Tivo (unplug power cord, or better yet, switch in connector for power) when plugging/unplugging the eSATA cable. In my case i have successfully used 2 meter eSATA cables.
According to Wikipedia, eSATA connectors are designed for 5,000 matings, that should hopefully much longer than the life expectancy of the Tivo.
5.4 Backup strategy
I now have a second 2TB drive in an external eSATA case. I plan to regularly do a full backup to it: Switch off Tivo. Disconnect the eSATA loopback cable from connector2, connect to a PC. Switch on Tivo again. Given how the Tivo itself is now not connected to the disk it will just hang, but as there is no advanced logic to shut itself down, it will nicely continue to provide power to the internal disk. Once done, pull power, reconnect internal disk via loopback cable, reboot.
For full backup, i just use "pv" under linux on my HTPC sitting next to the Tivo:
pv -ptera /dev/sdb > /dev/sdc
where sdb is the original and sdc is the backup. "pv" shows you nicely the progress and ETA. Full backup of 2TB takes less than 6 hours.
5.5 Recovery strategy
If there is a problem with the internal drive, you can simply connect the backup drive to continue using the Tivo (without the latest recordings of course).
You can also just connect the Tivo built-in drive to a PC an diagnose it. As always, i recommend to only change the external eSATA cable when the Tivo is switched off.
When drives start to have bad sectors, writing back a full backup can help to extend life because the drives firmware will reallocate sectors. This is primarily useful when the bad sectors have hit the linux partitions and rendered the Tivo inoperable. While i did not have this case on a Tivo yet, i did have PC hard disks showing few bad sectors mid-life. Once the drive is old enough, its likely better to replace.
These days, the quiet drives only come up with a warrante up to 3 years, so a tivo might actually live much longer than the drive...