gptgen-users — User-level discussion of gptgen.

[Gptgen-users] GPTgen result success but still MBR

[Xiao, S. <sco...@pl...>]

Hi anyone can advise what's wrong with the GPTgen? I used it on win2008 server VM to change the D: to GPT from MBR. the command line result shows success, but it still shows MBR when I use disk manager to view. The diskpart show has no * sign for the drive. Any advice please?Thanks!
Regards.
Kongfu

Re: [Gptgen-users] gptgen for Linux

[Sergey A. K. <ser...@ma...>]

Friday, July 17, 2009, 5:20:18 PM, Gábor wrote:

> I CCed the mailing list because this might be of interest to other people.

No prob :)


>> Yes, I've found this, but still had compilation problems. After I've
>> added these changes
>>
>> # diff -u /home/gptgen-0.1/gptgen.cpp ./gptgen.cpp
>> --- /home/gptgen-0.1/gptgen.cpp 2009-07-17 11:58:48.000000000 +0100
>> +++ ./gptgen.cpp        2009-07-17 12:17:14.000000000 +0100
>> @@ -32,7 +32,9 @@
>>  #else
>>  #include <fcntl.h>
>>  #include <linux/fs.h>
>> -#include <sys/ioctl.h>
>> +#include <sys/ioctl.h>
>> +#include <string.h>
> These look odd; it should be just "#include <string>", and both
> <string> and <algorithm> should be included by one of the headers
> already added.

Well, on Linux with commented out
//#define WE_ARE_WINDOWS 1
only I receive these errors:

# g++ ./gptgen.cpp -o gptgen -Wall
./gptgen.cpp: In function 'uint32_t crc32(const unsigned char*, long unsigned int)':
./gptgen.cpp:257: warning: comparison between signed and unsigned integer expressions
./gptgen.cpp: In function 'int read_tbl(std::string, uint64_t, int, char*)':
./gptgen.cpp:385: error: invalid conversion from 'unsigned char*' to 'char*'
./gptgen.cpp:385: error:   initializing argument 1 of 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::read(_CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>]'
./gptgen.cpp: In function 'int main(int, char**)':
./gptgen.cpp:603: warning: comparison between signed and unsigned integer expressions
./gptgen.cpp:768: warning: comparison between signed and unsigned integer expressions
./gptgen.cpp:506: warning: unused variable 'buf'
./gptgen.cpp:743: warning: label 'fallback' defined but not used

How can I solve this correctly?


> And what is the sys/ioctl.h change?

Nothing - I just played with it :)


>> But it seems gptgen does not write new table to disk even with -w
>> flag:

> This is one of the multiple problems with SIMPLE_LINUX_RW.

OK, how can I compile gptgen for Linux and get it working? :)


> This is because there is no such thing as a "boot flag" in GPT; you
> need to create a BIOS boot partition (GUID
> 21686148-6449-6E6F-744E-656564454649), or for EFI-based systems, an
> EFI system partition (GUID C12A7328-F81F-11D2-BA4B-00A0C93EC93B) and
> install a suitable boot loader (such as GRUB for BIOS or Elilo for EFI
> - AFAIK regular Lilo doesn't support GPT) on it. See
> http://grub.enbug.org/BIOS_Boot_Partition

Well, I use Gentoo Linux with patched grub to support GPT:
http://bugs.gentoo.org/show_bug.cgi?id=178586

When I write GPT table using dd command, I get unbootable server. I
used this command to create bootable partition:

# parted /dev/sda set 0 boot on

Maybe this is a reason, but maybe the reason is VMware - I use it for
testing. It emulates Intel 440BX hardware which BIOS may not recognize
GPT. What do you think?


My initial problem - I have backup server on colocation with 4TB RAID
array. It was partitioned by fdisk and uses standard DOS partition
table and has 2TB partition limit.

I'd want to switch to GPT partition smoothly and then resize 2TB
partition with data up to 4TB.

I hope it will be possible with gptgen :)


Thank you!

-- 
Sergey