Seriously!

Go Back   Seriously! Forums > General > Off Topic Forum

Off Topic Forum Discuss anything and everything in this forum.

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 09-05-2004, 04:58 AM   #1   Add To Ignore List  
.
 
sartophiketle's Avatar
 
Joined: Apr 2001
 
sartophiketle is offline Send a message via ICQ to sartophiketle
Default HDD Question (Block Size)

Ok, I'm a little rusty when it comes to the tech specs of reading/writing to a HDD, actually i haven't looked into it in about 6yrs but thats beside the point.... Basically atm I'm setting up a Highpoint Rocket Raid 454 card and using Raid 5, what I'm wanting to know is what block size I should be using for the best speeds on a WD120Gb HDD, actually several 120Gb drives (because obviously you need a minimum of 3 HDD's for Raid 5),

the majority of file sizes on the drives will probably be bigger rather than smaller, more than likely video... i seem to remember this was factored into things when choosing because of the size of the sector you wanted to use... would i be right in assuming the block size and sector size are the same thing? The Highpoint site keeps talking about block sizes (kb) and the western digital site refers to sector sizes (kb)... if this is the case then it looks like 512k blocks is what i should be choosing as the WD site mentions 512k secotrs sizes in it's tech specs but i want to make sure of things before i go ahead.

i came across this page but from what i could gather there didn't seem to be a hugh deal of different in the higher end of the scale of block sizes (256k, 512k, 1024k)

http://www.xbitlabs.com/articles/sto...22hdd-120.html

any help would be muchly appreciated.
__________________
I AM Serious Sam, and you're no friend of mine. - Booger
  Reply With Quote
Old 09-05-2004, 06:22 AM   #2   Add To Ignore List  
Your ad here.
 
Entroper's Avatar
 
Joined: Mar 2001
 
Entroper is offline
Default

The block size is the size of a chunk of data in the RAID array. I assume you know how RAID 5 works, since you're setting up a RAID 5 array. Basically, if you have 3 drives and a block size of 256kB, then 256kB will be written to disk A, then 256kB to disk B, and 256kB of parity to disk C. 256kB is actually a somewhat large chunk size for a RAID array.

Sectors don't mean as much as they used to. The WD site mentions 512 byte sectors, not 512kB. In the old days, a sector, head, and track used to correspond to an exact location on a physical disk. Unfortunately, due to limitations on the number of heads, sectors, and tracks, hard drives now use a system called LBA to 'fake' these things. The layout of data on the disk is managed by a chip on the hard drive, which translates everything into heads, sectors, and tracks for the IDE interface. The amount of data per track isn't even consistent anymore; you can see this in hard drive benchmarks, where transfer speeds are greatest near the outer edge of the drive, just like CDs.

Anyway, what this boils down to is that sector size and track size are no longer good guidelines for the block size of a RAID array. You just have to use your judgement based on what the array will primarily be used for. 64kB is a pretty standard size, but if you're going to be storing mostly video as you say, you could go a little larger. I wouldn't go any bigger than 256kB, as you probably won't see any performance benefit, and if you're going to use the drive for other stuff too, I'd try 128kB.
__________________
Entroper
https://www.twitch.tv/entroperzero
https://www.youtube.com/channel/UCUI...Fx5PjTSXHRf2yg
Virus and antivirus free since 1999.

If at first you don't succeed, you fail.
  Reply With Quote
Old 09-05-2004, 09:06 AM   #3   Add To Ignore List  
ZEN
roll'n ana stroll'n
 
ZEN's Avatar
 
Joined: Aug 2001
Location: Minn. USA
 
ZEN is offline
Default

Ok maybe this is nothing but a considerasion may be format or rather which allocation table.

Since your useing raid you choose what gives you funtion and speed.

Chooseing one over the other has more or less conseqences,..lets see.

smaller blocks fit better when the partision walls are an odd number minimizering the loss of space so more efficent when considering adding extended logical dos drives for the array.

That would be the NTFS format.
The FAT32 works well too if you use a little common sence,.I jsut patition the boot secter whith what ever leaves an even number for the remaining 4 drives again minimizeing loss.

I notice the large blocks are nice for large files,..faster,.. though the smaller system is a bit steader with with multi tasking.

Just a couple of thoughts on the subect.
__________________
Great men do not aspire to work ... they thrust it upon others.
.oOZEN]:::::o Chase to the cut.
  Reply With Quote
Old 09-06-2004, 05:34 PM   #4   Add To Ignore List  
is a loser.
 
McFuggin's Avatar
 
Joined: Jul 2002
Location: Central Maine
 
McFuggin is offline Send a message via AIM to McFuggin Send a message via MSN to McFuggin
Default

I'm going to be setting up a RAID5 array consisting of 6 80 Gb drives, soon. It's going to store backups of my DVD's and such (4-9 Gbs per file) in addition to documents, other random stuff, and an OS installation. What would be a better striping size for that? I'm thinking 64Kb (max size for the controller, I believe. SX6000 is the model number).
__________________
Apathy or ignorance?
  Reply With Quote
Old 09-08-2004, 04:32 AM   #5   Add To Ignore List  
.
 
sartophiketle's Avatar
 
Joined: Apr 2001
 
sartophiketle is offline Send a message via ICQ to sartophiketle
Default

Quote:
Originally Posted by Entroper
The block size is the size of a chunk of data in the RAID array. I assume you know how RAID 5 works, since you're setting up a RAID 5 array. Basically, if you have 3 drives and a block size of 256kB, then 256kB will be written to disk A, then 256kB to disk B, and 256kB of parity to disk C. 256kB is actually a somewhat large chunk size for a RAID array.

Sectors don't mean as much as they used to. The WD site mentions 512 byte sectors, not 512kB. In the old days, a sector, head, and track used to correspond to an exact location on a physical disk. Unfortunately, due to limitations on the number of heads, sectors, and tracks, hard drives now use a system called LBA to 'fake' these things. The layout of data on the disk is managed by a chip on the hard drive, which translates everything into heads, sectors, and tracks for the IDE interface. The amount of data per track isn't even consistent anymore; you can see this in hard drive benchmarks, where transfer speeds are greatest near the outer edge of the drive, just like CDs.

Anyway, what this boils down to is that sector size and track size are no longer good guidelines for the block size of a RAID array. You just have to use your judgement based on what the array will primarily be used for. 64kB is a pretty standard size, but if you're going to be storing mostly video as you say, you could go a little larger. I wouldn't go any bigger than 256kB, as you probably won't see any performance benefit, and if you're going to use the drive for other stuff too, I'd try 128kB.
thanks for the advice.. some of it i knew, some i didn't.. I've got the raid array set up but i thought raid write speeds were meant to be much faster than this, it's taking about 10mins+ to copy 4.5Gb onto the array.... maybe thats normal but it doesn't seem quite right to me.
__________________
I AM Serious Sam, and you're no friend of mine. - Booger
  Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
The Great Serious Sam 2 FAQ Discy Serious Sam 2 74 04-21-2012 07:43 AM
Question Question Ouwtou{UTW} Serious Editor 13 08-31-2002 03:47 PM
Texture Size Question Cthulhu The Deity Serious Editor 2 04-19-2002 02:06 PM
Beginner's Tutorial: Moving Brush Destruction CarlBillen Serious Editor 7 03-31-2002 12:06 PM
TIDBIT #14 - Viewable Size Chris1 Serious Sam Classic 4 09-11-2001 08:15 PM


All times are GMT -4. The time now is 07:27 PM.