This parameter allows an administrator to tune the allocation size reported to Windows clients. This is only useful for old SMB1 clients because modern SMB dialects eliminated that bottleneck and have better performance by default. Using this parameter may cause difficulties for some applications, e.g. MS Visual Studio. If the MS Visual Studio compiler starts to crash with an internal error, set this parameter to zero for this share. Settings this parameter to a large value can also cause small files to allocate more space on the disk than needed. This parameter is deprecated and will be removed in one of the next Samba releases. The integer parameter specifies the roundup size in bytes. 0 1048576(to set it to the former default of 1 MiB)