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Delete file slowness

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A component to control process creation and termination in Windows and .NET applications.
#13677
Posted: 06/15/2010 08:45:37
by Stefano Ricci (Standard support level)
Joined: 03/15/2010
Posts: 4

Hi
I'm experiencing very long delete file time in an application (written in C) using SOLFS (standard).
Slowness is experienced on a win2003 (SBS), using a Xeon processor and 3GB Ram.
I added some trace to my code and tracked down that a single StorageDeleteFile() can take up to 25 minutes to complete.
I understood (from forum threads) that StorageDeleteFile() does not actually delete and shrink storage, so I'm not able to figure out what is the problem on that system.

any tip?
thank
Stefano
#13680
Posted: 06/15/2010 09:01:39
by Eugene Mayevski (EldoS Corp.)

Set AutoCompact to 0. When AutoCompact is 25 (percent, the default value), it can be that the storage is really shrinked.


Sincerely yours
Eugene Mayevski
#13682
Posted: 06/15/2010 11:49:04
by Stefano Ricci (Standard support level)
Joined: 03/15/2010
Posts: 4

First tests using AutoCompact = 0 are ok.
thank you!

Unfortunately a new slowness has surfaced, this time on StorageReadFile().
I'm using a 1MB buffer to read file, and I saw a few cases where reading a file of less than 100KB took up to 10 minutes.
Do StorageReadFile() benefit of AutoCompact too (in this case I cannot understand why)? Or should be an issue with buffer size (too large)?

thank you for your help
stefano
#13685
Posted: 06/15/2010 14:24:43
by Eugene Mayevski (EldoS Corp.)

Please describe the storage in details: the size, the number of files total, number of files in the directory you read the file from etc.

If the file is not confidential and has reasonable size (up to several Gb), you can put it for download somewhere and send us the link via HelpDesk so that we could check the issue ourselves.


Sincerely yours
Eugene Mayevski
#13686
Posted: 06/15/2010 17:02:48
by Stefano Ricci (Standard support level)
Joined: 03/15/2010
Posts: 4

Hi
my application is reading files from solfs to save them to ntfs.
Files, once saved on ntfs, are deleted from the storage.
For this reason I'm not able to send you the storage file (even because it contains confidential data, to be honest).

as an example, at a certain point, I had to read a file of 2868 Bytes.
The storage was about 26MB and contains two folders.
The folder hosting the file I read, contains 15 files (16.5GB)
Reading that small file took 1889 seconds.

I noticed that I experienced long read time on small files (not every small file, indeed).
I have this behaviour on a single system (and not, for instance, on my developing machine - where everything works well)

kind regards
stefano
#13687
Posted: 06/16/2010 01:03:46
by Alexander Plas (EldoS Corp.)

Hello

It looks like some hardware problem. Can you check the System Event Viewer on the system where the problems are for any unusual errors or warnings related to the disk I/O?
#13688
Posted: 06/16/2010 01:33:05
by Eugene Mayevski (EldoS Corp.)

Also check if you have an antivirus installed - it can be that the antivirus attempts to scan the data on-the-fly, and certain sequences of bytes cause it to slow down.


Sincerely yours
Eugene Mayevski
#13689
Posted: 06/16/2010 02:45:00
by Stefano Ricci (Standard support level)
Joined: 03/15/2010
Posts: 4

Hello,
Unfortunately (or not) there are non errors/warnings related to disk I/O.

Symantec Endpoint Protection Small Business Edition is installed on the system, but it is configured not to scan the folder containing storage files.
I will check if it is possible to turn off AV for a while.

kind regards
stefano
#13690
Posted: 06/16/2010 04:16:15
by Alexander Plas (EldoS Corp.)

Nevertheless, give us please the properties of the storage: size of the storage (I assume that it is 25 GB not MB), free space in the storage, page size, encryption and compression if any.
Also by EldoS: Rethync
The cross-platform framework that simplifies synchronizing data between mobile and desktop applications and servers and cloud storages

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