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1994-02-02
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23KB
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444 lines
Version 1.3 of BFFSTool Distribution is 2-Feb-94
-----------------------------------------------------------------------
BFFSTool - a program to monitor and modify the behavior of running
BFFSFileSystem handlers.
BFFSTool provides a graphical "point-and-click" interface to the
internal operation of a running BFFSFileSystem handler. The tool
performs modifications to the running filesystem by directly
manipulating static BFFS local variables. This means that all
changes done by the user happen immediately and can be observed
while the tool is still running.
Don't be afraid to try the different buttons. There should be
nothing you can do in BFFSTool to damage your filesystem or
permanently impair its performance.
After starting up the filesystem, you may at first be overwhelmed
with the amount of information presented. Since this tool was
developed during debugging of the filesystem, you may find many
statistics not useful to you at all. First I will cover the
meaning of each static, then the buttons and other gadgets will
be explained.
You can start BFFSTool by typing "bffstool" at the CLI prompt.
It will automatically search the system for all accessed (and
valid) BFFS filesystems and choose the first one found to be
displayed. If you know the name of the device for BFFSTool to
initially select, you may specify that on the command line;
ie: "bffstool bf0:"
A window should open with the title, "Berkeley Fast Filesystem
(BFFS) status tool V1.3" If it doesn't then no handlers were
found in the system. In that case, you will need to consult
the documentation for correctly installing a BFFS handler.
If you have a handler installed correctly, you may have one of
two problems. The partition must be mounted and accessed
before BFFSTool will recognize the filesystem handler as valid.
The other possible problem may be that you are attempting to
run BFFSTool with the wrong version of the BFFSFileSystem.
BFFSTool 1.3 will ONLY work with version 1.3 of BFFSFileSystem.
The window should look similar to the following:
_____________________________________________________________________________
|_|_________________________________________________________________________|
| read hits 0 read opens 0 frags free 7 | Refresh ||
| read misses 0 read groups 4 blocks free 0 +-----------+|
| write hits 0 read bytes 4096 inodes free 23 | Sync ||
| write misses 0 write opens 0 num dirs 1 +-----------+|
| cgread hits 0 write groups 0 frag size 1024 | Clear ||
| cgread misses 0 write bytes 0 block size 8192 +-----------+|
| cgwrite hits 0 locates 0 num inodes 64 | Quit ||
| cgwrite misses 0 examines 1 data frags 679 -------------|
| cache moves 0 examinenexts 7 num frags 720 _ |
| flushes 0 flushes 0 num cgs 1 Auto Symlink |x||
| cg flushes 0 renames 0 num cyl 80 Ignore Case |x||
| force writes 0 sec/track 9 Link Comments |_||
|cg force writes 0 sync timer:1 track/cyl 2 Inode Comments | ||
| destroys 0 sync stalls:10 cyl/cg 80 +-+|
| invalidates 0 GMT offset:0 frags/cg 720 Unix Paths |_||
| cg max buffers:3 PreAlloc 7 inodes/cg 64 Read Only | ||
| max buffers:32 minfree 0 +-+|
| total buffers 32 media start 0 modified 0 Show Minfree |_||
| in use buffers 0 media end 737280 clean 0 Grp/Otr Bits |_||
| dirty buffers 0 version 1.3 Rw ____________________|
| locked buffers 0 disk type Sun md0a Handler |@|______BFFSa:_____||
|___________________________________________________________________________|
Note that the above is my best ASCII representation of a graphic display.
CACHE INFORMATION:
------------------
read hits The number of successful probes in the cache by the cache
module for the requested disk fragment. In general, this
number is slightly inflated because routines outside the
cache will often reaccess a block many times. For later
versions of the filesystem, this number will actually be
lowered because more routines will start to use the new
disk frag locking mechanism offered by the cache.
The main disk fragment cache is LRU based, but the data
structure features both sequential (ordered) and hashed
access for fast block lookups. Allocation for this
cache occurs at filesystem started and whenever buffers
are added or subtracted. Note that not all reads pass
through the cache and thus will not be reported as hits
or misses. Most notably, you will not see superblock or
multiblock reads/writes noted in the cache information.
This tends to push the cache hit rate up as those direct
accesses would most often be cache misses.
read misses The number of failed cache probes which required a disk
access to satisfy the request.
write hits The number of successful probes in the cache to access
a disk fragment such that the fragment will have to
eventually be written back to disk. A disk fragment
must already be in the cache as either clean (has only
been read so far) or dirty (has been written at least
once since the last flush) to be considered a hit.
write misses The number of failed cache probes which required a disk
access to cache the disk fragment to be modified.
cgread hits A separate cache module controls access to the cylinder
group summary cache. Each cache nodes contains a chunk
of memory as large as the disk block size. Cached in
that space are working cylinder group bit fields
describing the allocated and free blocks in the active
cylinder group(s). This cache is also LRU ordered, but
is not hashed because in general very few cylinder
groups should ever be active at the same time. The
larger your files and the smaller your disk, the less
individual cylinder groups I recommend.
cgread misses The number of cache misses for cylinder group summary
information. Note that cylinder group summary
information is only needed by the filesystem when
writing to the disk. If you never write on the
filesystem, then no memory will be allocated to the
cylinder group cache (allocation for this cache is
strictly dynamic, but bounded).
cgwrite hits The number of cache write hits which were satisfied
with cylinder group summary information already present
in the cache.
cgwrite misses The number of cache write misses which required a disk
access to satisfy the request to modify cylinder group
summary information.
cache moves The number of disk fragments moved around on the disk
via the cache write-back policy. Cache moves often
occur when writing files to the disk because at file
close, the policy of the Berkeley filesystem states
that the filesystem must attempt to locate a partial
filesystem block to put the last (incomplete) file
fragments. The cache moves take advantage of the
possibility that the data to be moved is probably still
in the cache, alleviating disk access.
flushes The number of cache flushes which were requested by
the filesystem. You may have started to realize that
the cache acts as an individual entity when it comes
to disk data. No other routines in the filesystem are
privy to the information the cache has. Flushes can
occur for various reasons, but will only happen when
the cache has dirty disk fragments to be written:
o The large block read or write routines are starting
a data access.
o The file deallocator wants block access to the
filesystem inode blocks (this also causes
invalidates of those fragments to occur).
o The cache was asked to get a disk block fragment,
but all cache slots are in use and the cache is
more than 3/4 full. ** This 3/4 will become a user
configurable setting in the next release. **
o The write back timer expires demanding the data be
flushed to the disk immediately.
o The user sends a ACTION_FLUSH or ACTION_DIE packet
to the filesystem.
cg flushes The number of cylinder group summary cache flushes which
were requested by the filesystem. These flushes can
happen under any of the following circumstances:
o The cache was asked to get a cylinder group summary
block which was not in the cache, and the cache was
already full with other cylinder group summary blocks.
Only the cg summary block ejected will be immediately
flushed to disk.
o The write back timer expires demanding the data be
flushed to the disk immediately.
o The user sends a ACTION_FLUSH or ACTION_DIE packet
to the filesystem.
force writes The number of cache disk frags which were requested by
the filesystem to be written immediately to the disk.
Also, the number of cache frags which were forced out
of the cache by the cache being full of dirty frags
when a new disk frag was requested.
cg force writes The number of cylinder group summary blocks which were
dirty and forced out to disk when accesses to other
cylinder group summary blocks forced them out. In
general, this value should be zero even in an really
active system. If it isn't zero, I suggest bumping the
number of cg max buffers.
destroys The number of times the entire cache was deallocated.
In general, this will only happen on disk change
invalidates The number of time the filesystem asked the cache to
"just forget" about specified cache frags. This will
happen to the destination of a cache move (if it exists
in the cache), or in the direct block write routines
should a large write chunk overlap a cached disk
fragment still in the cache.
cg max buffers This is a configurable maximum number of cylinder group
summary slots (filesystem block size memory chunks)
which are to be dedicated to caching cylinder group
summary information.
max buffers This is a configurable maximum number of disk fragment
size memory blocks which are dedicated to the main
disk fragment cache. This number is translatable into
the number of buffers reported by AddBuffers; however
AddBuffers reports this value in 512 byte blocks. This
may change as it's really just BFFS's interface with
the AddBuffers command.
total buffers The number of disk buffers allocated by the filesystem.
In general, this number will be the same as the max
buffers, except when the max buffers are changed from
inside BFFSTool. In that case, the change will not
take effect until the next disk change, or the next
AddBuffers command.
in use buffers The number of cache disk fragment buffers currently in
use by the filesystem.
dirty buffers The number of cache disk fragment buffers which have
not yet been written to disk. Usually, this value will
be zero unless the filesystem is busy writing files.
locked buffers The number of disk fragment buffers which have been
internally locked by the filesystem. In general, you
should /never/ see this value other than zero. This is
because the internal routines will unlock buffers
before completion of a packet.
GENERAL HANDLER INFORMATION:
----------------------------
read opens The number of files (successfully and unsuccessfully)
opened for read from the disk.
read groups The number of raw disk transfers which have been
requested of the disk device to read.
read bytes The number of bytes which have been requested of the
disk device read.
write opens The number of files (successfully and unsuccessfully)
opened for write to the disk.
write groups The number of raw disk transfers which have been
requested of the disk device to write.
write bytes The number of bytes which have been requested of the
disk device write.
locates The number of times an individual file was locked
via the ACTION_LOCATE packet (Lock() in dos.library)
examines The number of examine packets which have been sent
to the filesystem handler by AmigaDOS.
examinenexts The number of examine next packets which have been
sent to the filesystem handler by AmigaDOS.
flushes The number of times the cache was flushed by a timer
expire or by an ACTION_FLUSH packet send manually.
renames The number of files which have been renamed since this
handler was started up.
sync timer The number of seconds idle write packet time (no write
packets have been received within this time) to flush
out the cache data to disk. This is so when the
filesystem is idle, it can put the disk to use writing
back all the cached dirty disk data (and turning the
floppy motor off).
sync stalls The number of seconds to retry (check is once every
sync timer seconds) the cache flush before forcing a
cache flush anyway. This serves two purposes:
o Even in an system actively writing to the disk, the
filesystem gets a chance to checkpoint and sync
a consistent filesystem structure "often."
o Flushing out the cache improves performance in an
active system since those dirty fragments become
unavailable for regular filesystem use until they
have been synchronized with the media.
GMT offset The number of hours (plus or minus) that the local
time varies from GMT time. This is mainly used to
synchronize your AmigaDOS timestamp with the UNIX
file timestamp (which is always GMT).
PreAlloc Representation of the current BFFS settings usable
if you want to mount with those settings as default.
media start This is the byte address of the physical disk where
the active filesystem partition is being accessed.
media end This is the upper bounding byte address of the
physical disk where the active filesystem partition
is being accessed. All data accesses are checked
for validity within this range (to prevent media
corruption causing additional possible corruption).
version This is a comment field by the filesystem to describe
the current running version of BFFS. You will notice
the version number followed by some letters. The
letters you see detail the following:
R Handler can handle removable media. Your version
will probably have this option turned on.
E Handler uses extended packets to talk with the
disk device. Since not all devices are able
to use extended packets, your distribution
will probably have this option turned off.
F Handler compiled with Fast mode. This means that
all filesystem consistency checking is turned
off, but the filesystem performs much faster.
I Intel version. This version of the filesystem has
been compiled to support Intel byte ordering
for the filesystem (ie: 386i and 386BSD).
This automatically makes the filesystem
incompatible with Motorola byte ordering
filesystems, which include Sun SPARC, and
Amiga. This functionality is not yet
supported, but will be in a future release.
r Filesystem handler is compiled to only read the
disk and never allow writes.
w Filesystem handler is compiled to allow both reads
from and writes to the disk.
D Filesytem is compiled with debugging messages
turned on. This increases the size of the
filesystem and slows it down. Unless you are
running a non-distribution copy of BFFS, you
shouldn't see this flag.
The above flags are set at compile-time and can not
be modified by the user of the filesystem.
disk type This field presents information about what BFFS thinks
it is dealing with (as far as disk structure is
concerned). The first text (if present) is either
"Sun" or "BSD" if a disk partition label is present,
and was automatically sensed by the filesystem. Note
that if the Reserved parameter in the MountList is -1,
then this text will never show. If no disk label is
present, then the handler device name will be shown
instead. This field may also say "dev:Dsk?" indicating
no disk is in the drive. You may also see "dev:Bad?"
which means the superblock is unreadable. If you see
"dev:Dev?" this suggests a problem in the MountList.
If the disk was mounted successfully, the next part
will have the format "%cd%d%c" The first %c will be
the first character of the device driver. The %d is
the physical unit on that device. The last %c is the
partition that was actually mounted. So, for example,
if you have a Sun floppy in bf0: (and are using
messydisk.device or mfm.device , you should see:
"Sun md0a" Otherwise, if you have a Sun hard drive
at scsi.device unit 0, you may see "Sun sd0a"
SUPERBLOCK INFORMATION:
-----------------------
frags free The number of disk fragments which are not yet
allocated to a file. Note that this number should
stay relatively small, as the filesystem attempts
not to break full filesystem blocks if partial full
blocks (multiple disk frags) are located nearby.
blocks free The total number of full filesystem blocks which
have not yet been allocated to files.
inodes free The number of disk file descriptors still available.
If this number falls to zero, no mores files may
be allocated.
num dirs The number if directories present in the filesystem.
Note that the root directory counts as one.
frag size The number of bytes which make up a disk fragment,
as parameterized by the newfs command.
block size The number of bytes which make up a full filesystem
disk block as parameterized by the newfs command.
Note that this value must be a multiple (from 1x to
8x) the size of the frag size. Also, allowed values
for the block size are 4096, 8192, 16384, or 32768.
num inodes The total number of inodes which were parameterized
as available when the filesystem was created. By
subtracting the number of inodes free, you can get
the number of inodes in use.
data frags Number of total disk block fragments which are
allocatable to disk files. This is basically the
total filesystem size (num frags) minus the static
filesystem overhead allocation.
num frags The length of the filesystem in disk block fragments.
Note that this number is considerably more than the
actual usable space of the filesystem.
num cgs The number of individual disk cylinder groups
parameterized when the filesystem was created (newfs).
num cyl The number of disk cylinders involved in the entire
filesystem. This number is also chosen by newfs.
sec/track The number of sectors in a single disk track.
track/cyl The number of tracks (disk heads) in a single cylinder.
cyl/cg The number of disk cylinders parameterized by newfs
to be logically located in the same cylinder group.
frags/cg The number of disk block fragments per cylinder group.
inodes/cg The number of inodes parameterized by newfs to be
available (allocated within) each cylinder group.
minfree The minimum free disk space to report (percentage).
modified The number of modifications to the superblock since
the last flush. If this is non-zero, then the disk
is considered out of sync with memory.
clean This value should always be zero while the handler is
active with the disk. It is used to indicate in the
superblock that the filesystem was cleanly unmounted.
BUTTONS:
--------
Refresh This button asks the filesystem for an update on the
filesystem status information shown.
Sync This button asks the filesystem to FLUSH its dirty
cache disk fragments to disk immediately. You will
notice dirty buffers go to zero (unless the disk is
VERY active).
Clear Clear the value of the operating statistics. This
is a non-dangerous operation, as only data which
the filesystem /only/ updates is cleared.
Quit This button Quits BFFSTool, returning you to the CLI.
Auto Symlink This box allows you to turn on and off the automatic
symlink resolution of the filesystem. For this
release NEVER turn this flag off. ReadLink is not
implemented and most AmigaDOS programs will crash if
they run into a soft link and attempt to resolve it.
Ignore Case This box allows you to turn on and off the case
independence you have grown used to with AmigaDOS.
When off, multiple files may exist in the same
directory with the same name (just different case).
This may be necessary when trying to use a UNIX
filesystem with files such as "Makefile" and "makefile"
Link Comments This box allows you to turn on and off directory
comments for "special" files; symbolic links and
character/block special devices.
Inode Comments This box allows you to turn on and off directory
comments for files showing UNIX inode number,
permissions, uid, gid, number of links, nunber of
physical disk (512 byte) blocks, and number of bytes
allocated to the file. Note that directory listings
are faster if you do not normally use comments.
Unix Paths This box allows you to turn on and off the UNIX path
parser. When on / is a reference to the root
directory. When off, / is instead a reference to the
parent directory. Use this if you want BFFS to be
compatible with some unconfigurable package.
Read Only This box represents the superblock flag indicating
whether this filesystem is mounted read-write or
read-only. You may change this status at any time.
Show Minfree Checking this box makes the filesystem report
available disk space as relative to the minfree
percentage specified in the superblock.
Grp/Otr Bits This box when checked inverts the meaning of the
permission bits for group and other. Apparently
there was some late indecision made at Commodore
regarding the final meaning of these bits. This
provides a temporary solution should you need it.
Handler This is a Cycle gadget which allows you to choose
the BFFS handler with which you want to communicate.
Note that BFFSTool "knows" which handlers are active
in the system and it will only let you query an
active BFFS 1.3 or higher filesystem handler.
Finally, you will notice miniature up/down button gadgets near
"cg max buffers", "max buffers", "sync timer", "sync stalls", and
"GMT offset." These are for incrementing and decrementing the value
of the BFFS static parameter for the filesystem.
I hate documentation. ;)
Enjoy.
-----------------------------------------------------------------------
This package was written by Chris Hooper (cdh@mtu.edu).
-----------------------------------------------------------------------
