Il 18-01-2020 00:42 Darrick J. Wong ha scritto:
How many fragments, and how big of a sparse file?
A just installed CentOS 8 guest using a 20 GB sparse file vdisk had about 2000 fragments.
After running "fio --name=test --filename=test.img --rw=randwrite --size=4G" for about 30 mins, it ended with over 1M fragments/extents. At that point, reflinking that file took over 2 mins, and unlinking it about 4 mins.
I understand fio randwrite pattern is a worst case scenario; still, I think the results are interesting and telling for "aged" virtual machines.
As a side note, a just installed Win2019 guest backed with an 80 GB sparse file had about 18000 fragments.
Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx GPG public key ID: FF5F32A8
