PVR Hard Drive De-Frag?

[icefreon]

Do the PVR units do an automatic De-frag of the internal hard drive or is there a way to do it manually? The drive will get fragged over a period of time ( i assume) so I was just wondering.

[DmitriA]

For 721, someone should check the crontab and see what kind of maintenance scripts they have scheduled there

[Jacob S]

Can you imagine a hard drive that does not get defragmented over a period of years, especially a pvr satellite receiver that is used often? Some people do not defragment their hard drives on their own computers at home in which I bet is at least half the population if not more because they do not know anything that much about computers. I bet a lot of people do not delete their cookies and temp internet files either.

[gwynnebaer]

You'd be looking for some reference to xfs_fsr (http://linux.uni-regensburg.de/cgi-bin/man2html?xfs_fsr+8), which is the XFS filesystem defragmenter. Most references to XFS mention that this is a weekly cron job, so if it's not in the crontab, perhaps someone can add it and see if they can perceive any difference.

CAVEAT: Note that many people report issues (http://oss.sgi.com/projects/xfs/mail_archive/200203/msg00416.html) with running this command on a filesystem that is having issues. So you might want to see if we can get a straight answer from E* before someone hoses their Linux partitions. :D

[boomerang]

For what it's worth, I had a senior TSR tell me that the 721 will defrag only when the unit is off.

I asked him to define that. He said the unit is off when the green light is off.

[Big Bob]

I bet a lot of people do not delete their cookies and temp internet files either.

Why would you want to?
Where have you been that you don't want anyone to know about? :)

[Jacob S]

Because it takes up a lot of space on the hard drive over time doesnt it when it all adds up?

[Big Bob]

Because it takes up a lot of space on the hard drive over time doesnt it when it all adds up?

Actually, no it doesn't.

On this machine, with a relatively fresh install of win2000 and ie 5, the cache is set at 156 MB. Once 156 MB is stored on the drive, if anymore needs to be stored, the machine will delete the older files.

I believe 156 MB is the default from the install. This machine came with a 9 gig drive over 3 years ago. That makes the cache less than 2% of the drive. I don't feel that less than 2% is a lot of space.

If you know how to flush your cache, you should also be able to set the size of your cache to a size that works for you.

All that deleting your cache does it slow down your browsing.

Unless you have visited sites that you want no record of, I see no reason to delete the cache.

The cookie files take up almost no space at all.
And lets not go off on a tangent of the evils of cookies. That is an argument for a different group. :)

[Jacob S]

OK, did not know this. I thought I seen somewhere a setting for storage of cache.

[TomCat]

While I can't speak for the 721, having no direct info, there are storage strategies used on some PVR's that by their nature do not cause fragmentation at all. It would not be a surprise to me if every PVR used such a technique. If there is no down side involved, they probably all should.

On desktop computers and especially on PVR's, defrag is highly over-rated, the only real advantage being to companies like Alsoft and Symantech, who will gladly sell you utilities to help you accomplish this whether you actually need to or not. That's not to say that such utilities are unnecessary, because the repair and/or rebuilding of directories and other bundled utility routines that they also provide can be good prevention against potential disasters.

Defrag on a PVR gains you two very minor advantages:

1. Speed of access to files...hardly a concern on a PVR. The HD is much faster than the data rates needed to record or playback even multiple streams, so if this is an advantage, its a fairly insignificant one.

2. Cataloging. If a file can be stored contiguously it takes less cataloging to keep track of it, eliminating the need for an extents file altogether. This means that the directory info is simpler and less prone to corruption issues. This is only significant if the directory concering the file you are looking for is the one that becomes corrupt, and the odds are that there is then slightly more vulnerability with fragmented files, but not much.

[gcutler]

Would a periodic deleting of all programs help? Especially during the summer, my recoding is greatly reduced. I actually reached the point on my TiVo and 508 that I had nothing recorded. I'd assume that in itself (if there is a seperate OS and Data partition) would remove the need to defragment???

[TomCat]

Thats a good, or at least interesting question. I must admit that since I don't know as much as I wish I did I sometimes find myself operating under supertistious behavior patterns born out of that ignorance. For instance, when I reboot a video server I have found that I have better luck if I power down all the way and pull the plug for 30 seconds or so (seems to cause fewer secondary reboots for some reason) rather than just performing a warm restart of the OS. I have no real evidence that this can be helpful, other than peers reporting the same increase in success rate, but since it costs me little I try to do it that way every time.

Likewise, I don't know if my PVR's fragment or not, or whether certain patterns of operation are helpful to the cause or not, but I find myself doing things I think MIGHT be helpful. For instance I delete shows in the reverse order they were recorded whenever possible. If I've recorded "Friends" followed by "Scrubs", for instance, unless I'm in a particular "Friends" mood I will generally watch and delete "Scrubs" first, the reasoning being that once its gone it puts the PVR in the same exact state it was in before "Scrubs" was recorded and it can't contribute to fragmentation of the available pool of open recording space the way deleting "Friends" or any other previously recorded program might while a later recording still exists. Of course, I'd rather watch episode 23 of "24" before episode 24 of "24", so I don't take this practice to extremes, and it might do no earthly good at all. But I still do it, superstitiously. Whenever I actually clear a hard drive I try to do any available routines to reset things to the original state. I'm not sure that's helpful either. But I still do it.

[toad57]

For what it's worth, I had a senior TSR tell me that the 721 will defrag only when the unit is off.

I asked him to define that. He said the unit is off when the green light is off.

My DP7200 seems to exhibit this behavior... after powering down via the remote, the disk drive gets very 'busy' for a period of time and then finally settles down to no activity at all.