Drive Space Mystery

[BRUCE BROWN_2]

The total device volume is 50 Gb. When I do a dir command from the Master File Directory [000000] down it shows me that there are approximately 25 Gb worth of files. (dir /size DOMAINDATA01:[000000.])

I then did a "sh/dev domaindata01 /full" and it shows approximately 3 Gb free space. That leaves 12 Gb unaccounted for. I'm not sure what to make of that.

Thank You

Bruce

[Steven Schweda]

You mean

dir /size = all DOMAINDATA01:[000000...]

?

(And we should assume that DOMAINDATA01: is a
physical disk, not some odd-ball rooted
logical name?)

On a bad day, ANAL /DISK /REPAIR may change
things, but usually not so much.


From time to time, actual commands with
actual output can be less mysterious.

[Jan van den Ende]

Bruce,

like Steven wrote, actual commands and actual output leaves less to guess.

Here, without more info, there is a fair chance that the difference between ALLOCATED and USED space MIGHT explain things.
Especially if there are MANY files, and the drives have a BIG clustersize, that can take up a lot of space.
Further, if there are OPEN files (at the moment of the SHOW and/or DIR commands) that COULD have an influence.

The least we would need is the output of
$ SHOW LOGICAL DOMAINDATA01 and
$ DIR/SIZ=ALL DOMAINDATA01:[*...]

Show us the output; in a .TXT attachment

(and regular readers already know that I absolutely DETEST the :[000000...] construct!!)

Proost.

Have one on me.

jpe

[BRUCE BROWN_2]

SHOW LOGICAL DOMAINDATA01
"DOMAINDATA01" = "$1$DGA12:" (LNM$SYSTEM_TABLE)


$ DIR/SIZ=ALL DOMAINDATA01:[*...]

Grand total of 628 directories, 53594 files, 53296924/99130624 blocks

Sorry I cannot give you a listing of the files. We are running a healthcare system.

[Steven Schweda]

"99130624 blocks" looks to me like about 50GB.

> Especially if there are MANY files, and the
> drives have a BIG clustersize, that can
> take up a lot of space.

Yup. HELP INITIALIZE /CLUSTER_SIZE

pipe show devi /full DOMAINDATA01: | search sys$input "Cluster size"

> Sorry I cannot [...]

/GRAND is good enough for me.

[Hein van den Heuvel]

Get yourself a copy of DFU.
No ifs or buts, just get it.

Now:
$DEFINE DFU$NOSMG 1 ! Personally pet hate
$DFU REPORT DOMAINDATA01:
Pay extra close attention to the lines:

1) Total used/ allocated size
2) Total files (ODS2 / ODS5)
3) Directory files

Compare with DIRETORY/SIZE=ALL output if you feel like that.

Most like reason for 'missing block'.
1) used ($DIR/SIZE default) vs allocated space
1A) Over-allocated, with an eye on the future
1B) Simple cluste4r size oundup effect
1C) "Used" size not relevant for access method
-
2) Files NOT entered in a directory (perfectly legal, temp files)
:
99) corrupted disk structure
.

And, while I somewaht understand Jan's objection against [000000...] you may want to keep on using that over [*...] in order to automatically count in the space used by files in [000000].

Witness:
$ dir sys$sysdevice:[000000...]*.sys/grand/size
Grand total of 4 directories, 13 files, 1436678 blocks.
$ dir sys$sysdevice:[*...]*.sys/grand/size
Grand total of 3 directories, 4 files, 1101037 blocks.
$ dir sys$sysdevice:[000000]*.sys/grand/size
Grand total of 1 directory, 9 files, 335641 blocks.

Good luck!
Hein.

[BRUCE BROWN_2]

CERT>SHOW LOGICAL DOMAINDATA01
"DOMAINDATA01" = "$1$DGA12:" (LNM$SYSTEM_TABLE)
CERT>pipe show devi /full DOMAINDATA01: | search sys$input "Cluster size"
Cluster size 128 Transaction count 4474

DIR/SIZ=ALL DOMAINDATA01:[*...] /grand

Grand total of 627 directories, 53644 files, 53183165/98900352 blocks.

[BRUCE BROWN_2]

Get yourself a copy of DFU.

What is it and where can I find it?

[Hein van den Heuvel]

Ah, more data came in while replying.

Grand is Grand!

It does not look like clustersize roundup UNLESS... the cluster size is at least 1000+
It is more likely to be 95 or 128.

The worst-case waste would be if every singe file and directory would use just 1 block in the last extent (cluster). To make the missingle blocks work, the cluster size to waste 50M blocks would have to be:

$write sys$output (99130624 - 53296924 - 53594) / ( 53594 + 628 )
844

If the average waste is typically just over 50% of a cluster, not 99%, in which case the cluster size would have to be 2000-ish. Unlikely.

Back to DFU. Just use:

DFU SEARCH /OVER_ALLOCATED=10000 DOMAINDATA01:

hth,
Hein.

[Jan van den Ende]

Bruce,

>>>
Grand total of 628 directories, 53594 files, 53296924/99130624 blocks
<<<

53296924 blocks used, 99130624 allocated.

99130624 blocks = approx 49.5 GB.

The big difference can come from

- big disk cluster size.
The allocated size is always at least the used size rounded up to the next multiple of clustersize.
- big extend size
A file that needs more space normally grows with the extend size. (rounded up to ...)
The extend size can be defined at INIT time, overruled at MOUBT, overruled per process, overruled at file creation, overruled at file open. In short, not ONE fixed amount.
- a file that has grown much since the last OPEN. The EOF (for sequential, allocated amount, for other files something similar but more complex) only gets written at file CLOSE. (clean example: batch LOG files during the run always show 0/.
- file allocation cache; the system normally has about 10% of free space in pre-allocate cache. Those are not always reported correctly
- (usually the least interesting): an improper dismount does NOT "give back" the previous cache. (But a volume rebuild should cure that)

What is the most important in your case, only you can know.

hth

Proost.

Have one on me.

jpe