about tools/convert_imageset.cpp, how to append existing lmdb? how to speed up hdd read?

[gwang been park]

I have a speed problem with making lmdb...

My hdd has 20million number of jpg image files(32*32 gray image). (I can't use my ssd, because ubuntu inode capacity is full...)

And when i call tools/convert_imageset , It takes really lot of time to make lmdb...

So Is there any way to append existing lmdb?

Is there any way to speed up convert_imageset.cpp with hdd read?(especially with many small image files.)