Gene Heskett <ghesk...@shentel.net> writes: > On Monday 26 August 2019 23:55:31 Olivier wrote: > >> Gene Heskett <ghesk...@shentel.net> writes: >> > Generally speaking, only because the disc is random access. >> >> But a disk dedicated to vtapes should be doing a lot of sequetial >> accesses: once it has been formatted and the slots have been assigned, >> it is writting files the size of one Amanda's chunk. In fact, that >> would be worth a study: the disk usage for vtapes vs. normal disk >> usage. >> >> That is just gross figures but: >> >> Users' home directories: >> Filesystem Size Used Avail Capacity Mounted on >> /dev/da1p1 2.9T 851G 1.8T 31% /home >> 2565312 files, 223129681 used, 556890331 free >> (564355 frags, 69540747 blocks, 0.1% fragmentation) > > My Mail dir is on /home, dates back to about my 2nd install in 2001, with > probably north of 20 GB of maildirs, so I'd expect that is more than 1% > fragmented, but except for tde's kmail occasionally bucking about it, > has not been a major problem. Copying it to a new Maildir usually fixes > it for that particular list. Reducing the keep time for those lists > deemed not so important has also helped. About 3 lists I keep forever, > but 50 more are expired every 3 or 6 months.
That was given as an example only, to show that fragmentation grows faster on a file system supporting users' home directory tha on a file system supporting Amanda'a vtapes. I had rebuild the users' home directory on a new RAID array recently, that is why it is so little fragmented, but still much more than an Amanda disk that is much older. >> Amanda vtape disk: >> Filesystem Size Used Avail Capacity Mounted on >> /dev/ada5p1 2.6T 2.2T 269G 89% /automnt/ada5 >> 475 files, 582393950 used, 127171372 free >> (84 frags, 15896411 blocks, 0.0% fragmentation) >> >> The vtape disk is slightly older than the users' home, definitely >> fuller and less fragmented, so I would guess big sequetial files with >> little head movement. >> > I wondered about fragmentation myself, but it has never reared its head > in well over 15 years. Best regards, Olivier --
