data disk, fixed emplacement for zones

[doloop]

Hello all,

Im fairly new to MyDefrag, enjoying it and wanted to make my own customized scripts, starting with a script for a data partition of 183GB.
I wouldlike to have fixed places for zones ie :
0-1GB : MFT/Directories
1GB-50 GB : Zone w
50GB-60GB : zone x
60-110GB : zone y
110-140GB : zone z
140-endofDisk : last zone

However i have no idea how to specify the gaps to be fixed.

Can anyone help ?

[Darlis]

You can place zones wherever you want with MakeGap:

Code:

VolumeActions
  // Zone 1
  FileSelect...

  MakeGap(1GB) // place next zone at 1GB

  // Zone 2 is now placed at 1 GB
  FileSelect ...

VolumeEnd

Don't get confused: MakeGap is more like "set position" than "make a gap".

Btw. isn't 1GB for directories and MFT a bit much? Note that you can improve performance a bit if you place this zone further into the volume.

[doloop]

ok thanks a lot for your very quick answer.
i looked a lot at your scripts to learn.

i understand better how gaps works.

i thought mft and directory had to be placed at the beginning for faster access ?

1gb was to let a bit of room at the beginning of my partition but your right its useless as i just noticed data are written near where disk "pointer" is currently and not necesserely at the begining.

thanks again for your help. im planning to write scripts for servers soon (excluding exchange files).... when i will be better at scripting with mydefrag.

[doloop]

i will also add that its a logical partition, not a disk. so i guess its not that important if mft is at very begining or further ?

[Darlis]

The important part is the distance between the MFT and and the location where the most reads and writes occur. The further these positions are apart, the longer the disk heads have to travel.

For example, your zone w profits from being close to the MFT. If the MFT is placed after this zone, both w and x will get a small performance bonus.

[doloop]

ok i see. Thanks for these very instructive informations. Despite my average english you answer very precisely my questions.

Do you have any key informations about server defrag, especially with Raids ? Exchange ? and network shares ?

[doloop]

another quick question, in the case of a partitionned drive is it better than often accessed files on C are written at the end of the partition to be near often accessed's D: data ?

[jeroen]

Do you have any key informations about server defrag, especially with Raids ? Exchange ? and network shares ?

For servers you may want to use settings such as Slowdown and ProcessPriority. Raid volumes are fine, MyDefrag will handle them no problem whatsoever. Exchange can be a bit of a problem. If the Exchange storage is huge then defragmenting it can take a lot of time and this can cause Exchange to timeout for incoming mail. It is easily avoided by excluding the Exchange storage in MyDefrag with ExcludeFiles. Network shares generally cannot be defragmented, MyDefrag needs low-level access and can therefore only process local disks.

in the case of a partitionned drive is it better than often accessed files on C are written at the end of the partition to be near often accessed's D: data ?

Yes, generally speaking it is best for all frequently accessed data to be as close together on disk as possible. But MyDefrag is not really designed to put files at the end of the volume. There is basically only 1 command for that (MoveToEndOfDisk). You can use AddGap, but it's a bit of a kludge.

[Kasuha]

Raid volumes are fine, MyDefrag will handle them no problem whatsoever.

There is one MyDefrag "problem" which sometimes presents itself with relation to Raid volumes - MyDefrag needs certain amount of memory for each file on the disk it is processing. If there are many millions of files on the volume, MyDefrag can run out of memory and crash on such disks. The good thing is, it cannot break anything if that happens. On 32-bit version of MyDefrag, there is certain hard limit (32-bit application cannot handle any more than 4 GB of memory). I am not sure about 64-bit version of MyDefrag but there is always also limit of RAM in the machine.

[Darlis]

There is one MyDefrag "problem" which sometimes presents itself with relation to Raid volumes - MyDefrag needs certain amount of memory for each file on the disk it is processing. If there are many millions of files on the volume, MyDefrag can run out of memory and crash on such disks.

The amount of files has nothing to do with a RAID.

(32-bit application cannot handle any more than 4 GB of memory)

No, it's 2GB. If the program is compiled with a special switch it can use up to 3GB on x64 systems. But in the latter case you'll use the x64 version of MyDefrag anyway.

[Kasuha]

The amount of files has nothing to do with a RAID.

The problem may not be related directly but there remains the indirect relation that huge numbers of files usually appear on huge volumes which are usually RAIDs.

No, it's 2GB. If the program is compiled with a special switch it can use up to 3GB on x64 systems. But in the latter case you'll use the x64 version of MyDefrag anyway.

"For a 32-bit application launched in a 32-bit Windows, the total size of all the mentioned data types must not exceed 2 Gbytes. (Actually it is 1.75 Gbytes due to memory requirements of the operating system itself). A 32-bit program compiled with the switch /LARGEADDRESSAWARE:YES can allocate up to 3 Gbytes of memory if the 32-bit Windows is launched with the /3gb switch. The same 32-bit program launched in a 64-bit system can allocate about 4 Gbytes (actually about 3.5 Gbytes)."

http://www.viva64.com/en/k/0036/

But that's unrelated to what I was talking about, and that was that 32-bit MyDefrag can only handle disks with limited amount of files. Your statement doesn't change anything on that.

The more important fact is that even on 64-bit system, even 64-bit MyDefrag can run out of memory if there's less of it than needed to process the disk.

[Darlis]

The problem may not be related directly but there remains the indirect relation that huge numbers of files usually appear on huge volumes which are usually RAIDs.

In my company I have 3 RAID systems with a volume size of less than 1TB and only one with 2TB but the file count on this one is somewhere between 10 and 20.

"A 32-bit program compiled with the switch /LARGEADDRESSAWARE:YES can allocate up to 3 Gbytes of memory if the 32-bit Windows is launched with the /3gb switch. The same 32-bit program launched in a 64-bit system can allocate about 4 Gbytes (actually about 3.5 Gbytes)."

Ah, yes. That's where I got confused.

[Kasuha]

In my company I have 3 RAID systems with a volume size of less than 1TB and only one with 2TB but the file count on this one is somewhere between 10 and 20.

Therefore doloop is not going to have any problems with his RAIDs as long as he works in your company.
I have no problems with that.