I have:

define tapetype DLT4000-IIIXT {

    comment "DLT4000 with DLTtape IIIXT uncompressed"
    length 15000 mbytes
    filemark 8 kbytes
    speed 1536 kbytes
    lbl-templ "/usr/local/etc/amanda/common/DLT.ps"
}

define tapetype DLT4000-IV {

    comment "DLT4000 or DLT7000 writing DLT4000 format with DLTtape IV
uncompressed"
    length 20000 mbytes
    filemark 8 kbytes
    speed 1536 kbytes
    lbl-templ "/usr/local/etc/amanda/common/DLT.ps"
}


Is 8kb enough for the filemark ? My last amdump reported en error
writing filemark (But it ran fine for the past 2 months)

If I change the filemark length, will I be able to read my previous
tapes with amrestore/amrecover ?

Thanks