Hi Nedim,

I get an error saying that I have a reference to an invalid character number. The character U+0001 is valid in XML 1.1. Does this mean that Sedna does not support XML 1.1?

For historical and licence reasons Sedna uses expat XML parser which still doesn't support XML 1.1.
If that is the case, do you know of a way how to detect if a string contains characters which are not allowed by XML 1.0, so that I can convert them to base 64? I am using Xerces to convert my data into XML.

Java Xerces or C Xerces? Probably, it has XML 1.0 mode?
I also have a question regarding space consumption. I am running Sedna 3.5.95, I have loaded 100 XML files with the total size of 1.2GB into the database and the size of the data folder of this database is now 15GB. Is this normal? What ratio of raw XML data size and database disk usage should I expect?

It depends on data itself and the way you store it in Sedna (collections or standalone documents). 
Do you use collections?
What is the size of *.sedata file in the database folder? 

Ivan Shcheklein,
Sedna Team