How common is stuttering on 4K cluster size partitions, really?

[archcommus]

Hi, I know everyone here recommends a partition formatted with 64K clusters for HD recording and playback to avoid stuttering. I use a regular partition formatted to 4K clusters and experience no stuttering at all. My computer is a quad core Intel CPU with 4 GB memory and a Samsung 500 GB hard drive.

So my question is, how common is stuttering on non-64K cluster drives, really? Is this just an old recommendation that doesn't really apply to modern faster computers? If it's still very relevant today I'm curious why I'm not experiencing it.

Thanks.

[gplasky]

It's not the processor speed or the memory that is the issue. If you're recording HD you are guaranteed to get stuttering as you record and delete recordings if you're using 4k clusters. The huge files become so fragmented that it is the drive head that can't keep up with reading the file because it is spending most of its time flying all over the platter. DVD rips aren't usually an issue but HD recordings are.

Gerry

[jlmdxtv]

I've tested recording to a dedicated drive with 16K clusters on a modern dual-core system with a modern 750GB Seagate SATA drive. When recording 2 or more HD shows simultaneously, I experienced a slight (1/2 second) stutter - *in the recording* - about once every ten minutes per HD recording. I'd expect it would be much worse as the drive became fragmented.

john

[archcommus]

Originally Posted by gplasky

It's not the processor speed or the memory that is the issue. If you're recording HD you are guaranteed to get stuttering as you record and delete recordings if you're using 4k clusters. The huge files become so fragmented that it is the drive head that can't keep up with reading the file because it is spending most of its time flying all over the platter. DVD rips aren't usually an issue but HD recordings are.

Gerry

I see, thanks, didn't realize the issue really crops up when things get fragmented. The partition I'm using is dedicated to files, so it doesn't get fragmented much to begin with, and I run Vista's defrag once a week, currently it tells me my files partition is 0% fragmented and the programs partition is 1%. This is probably why I don't see the issue even with 4K clusters. I also don't keep recordings around for very long.

[Taddeusz]

Originally Posted by archcommus

I see, thanks, didn't realize the issue really crops up when things get fragmented. The partition I'm using is dedicated to files, so it doesn't get fragmented much to begin with, and I run Vista's defrag once a week, currently it tells me my files partition is 0% fragmented and the programs partition is 1%. This is probably why I don't see the issue even with 4K clusters. I also don't keep recordings around for very long.

Keep in mind that Vista's defrag ignores files that have extents that are 64MB or larger. In other words, if you have a 4GB file that is broken up into 3 pieces but no piece is smaller than 64MB it does not consider that file fragmented and ignores it.

https://blogs.technet.com/filecab/articles/440717.aspx

[heffe2001]

Originally Posted by archcommus

I also don't keep recordings around for very long.

Isn't this what causes fragmentation in the first place? Have say, show A B C & D (all 1hr) recorded, watch C, delete, show E (30 min) records in the blank spot between B & D, show F (1hr) records, half between B & D, half after D, etc...

Wouldn't a defrag system like perfect disk (has freespace defragmentation) help out more than just defragmenting the existing recordings alone?

[davephan]

I'd recommend using a separate drive for the operating system from the video storage drive, instead of partitioning one drive. Format the video storage drive with 64K blocks. Take periodic disk images of the operating system drive and store them on a separate USB hard drive. If you use separate operating system and video storage drives, it is easier and quicker to backup and recover when the computer needs to be recovered.

Dave

[bartley9]

There was a thread about this a while back. Another vry important factor is the amount iof I/O's you can issue against a disk. The time taken to write a 64K block is only very marginally longer than a 4K block. Most of the time is spent getting ready and positioning the heads, the write time is small.

With 64K clusters you will be doing 16 times less I/O's. Or to put it another way if you have multiple tuners or client you can support 16 times as many.

[archcommus]

Originally Posted by Taddeusz

Keep in mind that Vista's defrag ignores files that have extents that are 64MB or larger. In other words, if you have a 4GB file that is broken up into 3 pieces but no piece is smaller than 64MB it does not consider that file fragmented and ignores it.

https://blogs.technet.com/filecab/articles/440717.aspx

Thanks, I didn't know that about Vista's defrag. So it's possible another tool would report it more fragemented.

Deleting, recording, etc. frequently would definitley contribute to fragmentation. But I usually record like 2 or 3 shows max, then watch all and delete all. Considering the partition is completely just for data and is hardly written to, I think overall the partition doesn't get very fragmented.

Originally Posted by davephan

I'd recommend using a separate drive for the operating system from the video storage drive, instead of partitioning one drive. Format the video storage drive with 64K blocks.

I think multiple partitions is just as effective as separate physical drives for managing and backing up data. But, does a separate partition with 64K clusters work as well as a whole drive with 64K clusters for recording?

Considering supporting 16 times as many I/O's, I think that makes an important point that another big reason for 64K clusters is multiple simultaneous recordings, obviously going to lead to fragmentation. Again, something I don't do.

I think it's safe to say I don't experience stuttering (even with HD) because my files partition is rarely written to, I don't do simultaneous recordings, and I usually watch and delete shows in batches. But I understand that if my recording habits ever change then I would maybe have a reason to create a dedicated partition with 64K clusters. But I am curious if a 64K cluster partition on a drive is as effective as a whole physical drive formatted to 64K clusters.

[GKusnick]

Originally Posted by archcommus

But I am curious if a 64K cluster partition on a drive is as effective as a whole physical drive formatted to 64K clusters.

Partitioning a disk can help with fragmentation, but it doesn't change the fact that there's still just one read/write head. If you're simultaneously writing two files (e.g. a recording and a log file) to different partitions on the same physical disk, you're going to get more seeking (and lower overall performance) than if they're written to the same partition, or to different physical disks.

Another advantage to keeping your recordings on a separate disk is that it makes it easier to upgrade to a bigger recording disk as prices come down, without disturbing your boot disk. This may not seem like an issue for you now, but again, if your habits change (e.g. you decide to archive a whole season of your favorite show), those bigger disks may start to look tempting.