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Discussion Starter · #1 ·
I finally installed dedicated a disk subsystem exclusively for accessDTV recording/playback/pvr using:


1) Promise ata-100

2) IBM 75gig 7200rpm mode 5 drive


(My 2 super fast 10,000rpm ultra2 scsi drives are used for OS and apps)


Anyway, as a test, I formated the IBM IDE drive using 4096 bytes for "allocation unit size". In theory larger blocks are ideal for large multimedia files...to get the most throughput/performance you can get on large files. This is the first time I tried this.


I am curiosu if anyone knows if 4096bytes is the ideal block size for HDTV files when formating the drive. I can understand how this wouldn't be optimal for people who share their accessDTV "clip" drive with other smaller file types.


To give you an idea how well segregated my accessDTV disk subsystem is, I was defraging my Ultra2scsi drive while recording a show without the slitghtest glitch. However, I don't kinow how much the block size can help if if there is even a better select to choose from other than 4096.


Can someone shed some light on this for me?




[This message has been edited by mkanet (edited 05-14-2001).]
 

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I don't know what the optimum block size is but my setup is almost like yours and I can do just about anything I want on my machine without causing a wrinkle with accessDTV.


I wouldn't try [email protected] of course but I never hear a glitch when I do a playback.


I have 3 60GB Maxtor drives connected to the Promise ATA100 controller (obviously one pair is set as Master/Slave) and they are formatted with NTFS with the default block size.


I made them a volume set so it looks like one big 180 GB drive to Windows 2000. I do have some folders on it - like MSFT Office and Adobe Photoshop but it is dedicated mainly for accessDTV recordings.


When you get a second drive, give that a shot and see how well it works.


Joe
 

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Discussion Starter · #3 ·
I have an IDE volume set on my NT 4.0 file server formatted as NTFS with default block size under NT 4.0 (I have over 100 gigs of mp3s on that server) ata-66. It's actually perfect for mp3's.


You brought up a good point. I was soooo close to picking up a second 75gig IBM drive. However there are a few good reasons why I didn't. Who knows, I may change my mind later on...


1) I don't think I would add any performance by adding a second drive and raid0'ing it with IDE. IDE STILL cannot multitask reads and writes the way SCSI can. It would make much more sense to raid SCSI drives for performance. It's not so much more throughput performance I was looking for for accessDTV HDTV files (since a single ata-100 drive is more than adequate). However, I think in theory, a large block size in general can offer very reliable and fairly high sustained data rate for large files. However, It would be good to hear more feedback on this.


2) As for space, 75 gigs is plenty for me right now to "tape" shows/movies I've missed. I only "tape" a show/movie and watch it usually only once. The keepers are stuff like music videos or certain scenes from movies/animations.


3) I don't think hard drives are the ideal media for "archiving" full length HDTV movies. How can someone archive a library of 50 or more full length HDTV movies on hard drives? It would get pretty expensive. Instead, I am waiting for consumer high density double-sided DVD-R drives capable of recording 17.x gigs (perfect for HDTV movies)....not to be mistaken for (the not so useful) 4.x gig single sided DVD-R drives out now.


However, in fear of getting flamed, please keep in mind that the above are only my opinions and there is always a chance I may not have entirely accurate information. http://www.avsforum.com/ubb/smile.gif


I STILL would like to know if anyone can contribute to my block size question and what would be the ideal block size for ONLY large HDTV files.


To this date, I dont think IDE still is able to write and read all the drives at the same time like the way SCSI does. However, this is definitely the fastest IDE disk setup I've seen.


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-Michael

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For a filesystem which contains only large files and which will usually be accessed sequentially, the best blocksize will be the largest blocksize that you can choose. Increasing blocksize will decrease fragmentation and may also give you more usuable space because a lot of filesystem overheaed goes to accounting for blocks, less blocks means less overhead.
 

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I agree it wouldn't hurt to go to 8K block size. Note you'll have to format from the command prompt to specify a blocksize larger than 4K. NTFS can go up to 64K bock-size, and it might be interesting to benchmark and compare at the different sizes, but I think 8K is a good size because I'm pretty sure that the size of a 'page' of memory in NT.


About RAID-O not being worth it because IDE can't multitask: that's only true if the drives are master/slave on the same channel. Put each drive as the master on a dedicated IDE channel and it's not an issue.


Jeff
 

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Quote:
Originally posted by Joe Q:
I have 3 60GB Maxtor drives connected to the Promise ATA100 controller (obviously one pair is set as Master/Slave) and they are formatted with NTFS with the default block size.Joe
Have you tested for the Promise/Win 2K file corruption bug? It occurs when both channels on the Promise are active and you write a file larger than a few hundred megabytes.
 

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Quote:
I agree it wouldn't hurt to go to 8K block size. Note you'll have to format from the command prompt to specify a blocksize larger than 4K. NTFS can go up to 64K bock-size, and it might be interesting to benchmark and compare at the different sizes, but I think 8K is a good size because I'm pretty sure that the size of a 'page' of memory in NT.
Interesting topic. I have a similar setup to mkanet. I use SCSI-160 drives (running in U2W mode) for my OS and apps. They absolutely scream! Then I have a pair of IBM 75G drives for HD recording. I ran across this interesting comment from Format Help regarding NTFS -


"NTFS compression is not supported for allocation unit sizes above 4096."


I think it's been proven that some compression is possible with these files. I would like to run NTFS, but for the sake of compatibility with other systems, I will probably stick with Fat32.


Chris
 

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Discussion Starter · #8 ·
Hey Jeff,


Thanks for the tip. I reformatted the IDE drive to 8K. I don't have any good disk performance tools installed like "Sandra". However, I did notice when I copied about 5 gigs of large .adtv files from my Ultra2scsi to the IDE drive, it seemed to copy to the drive quicker than last time.


Does anyone know how to check the block size of a formatted drive after it's been formatted? It's not under properties, like I thought it would be.


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-Michael

[email protected]


[This message has been edited by mkanet (edited 05-15-2001).]
 

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Quote:
Does anyone know how to check the block size of a formatted drive after it's been formatted? It's not under properties, like I thought it would be.
Run chkdsk.exe from the command prompt and it will tell you in its summary.


Jeff
 
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