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Solid FS Compression

Also by EldoS: Callback File System
Create virtual file systems and disks, expose and manage remote data as if they were files on the local disk.
Posted: 06/02/2013 21:34:45
by Bhushan Manekar (Premium support level)
Joined: 07/18/2012
Posts: 10

I am running SOIFS Win32 C Sample application (C:\Program Files (x86)\EldoS\SolFS\Win32\Samples\solfsc)

I am facing one issue with respect to file compression in SOIFS.
Please let me know if you can help me.

First, Storage 'cp_no' is created and file 'sample2.txt' is added in storage without using any compression

Function used:

e = StorageCreateFile(st, wDstFullName, True, True, True, True,
pwd != NULL ? 1 : 0, pwd,
pwd != NULL ? strlen(passwd) : 0, &fl, True, True);

Later, Storage 'cp_yes' is created and file 'sample2.txt' is added in storage by using compression level as 3

Function used:

e = StorageCreateFileCompressed(st, wDstFullName, True, True,
True, True, pwd != NULL ? 1 : 0, pwd,
pwd != NULL ? strlen(passwd) : 0,
1, 3, 16, &fl, True, True);

When I open SOIFS solution explorer, I see same sizes for both files except file attribute is set as compressed in later case.
But file size is same in both cases.(63.94 MB)

I am attaching screen shots for quick reference.

Thank you very much.

Posted: 06/02/2013 23:29:30
by Eugene Mayevski (Team)

Size displayed for the particular file is a real file size, not compressed one (exactly like in Windows Explorer for NTFS compressed files).

There's no way to learn compressed size of the file in SolFS (and I doubt about the OS and NTFS files as well).

Sincerely yours
Eugene Mayevski
Posted: 06/03/2013 20:37:56
by Bhushan Manekar (Premium support level)
Joined: 07/18/2012
Posts: 10

Hello Eugene,

Thank you for prompt reply.
We are planing to use Solid FS where Data in on SAN.
While going through documentation, I found that there are two modes in which Solid FS can be used.

1) Default mode 2) Callback mode.

Callback mode would be useful if data is stored on the SAN ?
What are its advantages and disadvantages?

Kindly advise.

Thank you.
Posted: 06/04/2013 00:25:00
by Eugene Mayevski (Team)

By default SolFS uses file API to access the container file. In callback mode SolFS calls your functions to read and write pages (blocks) of the container. This lets you keep the data in a different way from the file, eg. in NoSQL DB (one page per record, as a variant). There's an article on Callback mode of SolFS here.

Sincerely yours
Eugene Mayevski
Posted: 06/04/2013 19:26:13
by Bhushan M (Basic support level)
Joined: 06/04/2013
Posts: 1

Hey Eugene,
I was testing the compression on different types of files in SolFS bucket and looks like Images/Song files gets no compression at all. On the other hand, I could see some magic on Text based files like Word when I used mode 'r' in file handle. Unfortunately I could not use 'r' mode for Images/Songs as they were getting corrupted when I tested retrieving them back from bucket. So, had to use 'rb' mode to put image files in bucket which worked but no compression.

Does that mean - no compression for Image/Song files or is there any way to achieve this?

Posted: 06/05/2013 00:19:17
by Eugene Mayevski (Team)

Images and songs come compressed nowadays, and you can hardly compress them further.

Now, "r" mode means text reading, in opposite to binary "rb". Of course, in text mode your binary data can be "corrupted", so text mode is generally not recommended to use - even if you need one, you should control the reading process yourself.

Sincerely yours
Eugene Mayevski
Also by EldoS: MsgConnect
Cross-platform protocol-independent communication framework for building peer-to-peer and client-server applications and middleware components.



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