8kblocks
Posted in 2003
Hi,
as documented shared memory is divided into a series of 8k blocks. Recently
I
met two IDS systems that seemed to contradict with this fact. Here's an
onstat -g seg output from a production system:
Segment Summary:
id key addr size ovhd class blkused blkfree
1801 1381386241 a000000 62078976 216664 R 15126 30
1802 1381386242 db34000 65536000 2600 V 12597 3403
1803 1381386243 119b4000 1716224 656 M 419 0
1804 1381386244 11b57000 1716224 656 M 419 0
1705 1381386245 11cfa000 16777216 1112 V 4054 42
1706 1381386246 12cfa000 16777216 1112 V 1734 2362
1507 1381386247 13cfa000 16777216 1112 V 1623 2473
408 1381386248 14cfa000 16777216 1112 V 747 3349
109 1381386249 15cfa000 16777216 1112 V 1 4095
Total: - - 214933504 - - 36720 15754
(* segment locked in memory)
The first virtual segment's size is 64,000 KB and has 16000 blocks... hmm.
Here's an onstat -g nbm output for the second virtual portion:
Block bitmap for virtual segment address 0x12cfa000:
address = 0x12cfa258, size(bits) = 4096
used = 1734, largest_free = -1
firstfree = 304, lastalloc=2559
0:ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
ffffffff
256:ffffffff ffff0075 bffe001f 8602dcfe 30a498ae ffce039a 3ffe0588
6e63e80e
512:bd552063 e42e4df6 669a411e 1e8e7ffe 36650404 39089421 e3006142
8807fee0
768:0aca0480 07fe4216 4e014c1c 8fdc3000 823ae759 cb410103 448048c3
8c00f7ff
1024:f3a1c852 43808fff c07f692c 29f91802 06574028 64041862 01012002
da6b9906
1280:45c107f3 e1802829 75012740 420a4d04 460290f3 02098802 00409850
0731ff9b
1536:11100c96 50a840a9 07407906 181a0202 482c4503 4211cb89 affb5597
89178b42
1792:5a65282d 0c50c128 46506654 40c48087 ffe3bf81 b89a82d6 f4877872
5c2f4810
2048:5ffc4c21 1ffc4002 82903a72 021f0c80 7fe3c086 8660c107 fc1083c2
9b084205
2304:c00cc1c0 05007384 8f00bc03 ca0a0138 2c102fff c2001570 5e2f600e
62059f72
2560:00002011 82041e5a 301d6000 00800000 0dc607c0 000a4000 01500000
4c004006
2816:58000871 18100ffe bffffe41 fffc0f80 4f49e1e8 10c0c1ff 20088054
2002b806
3072:6cf079b0 d1080502 2180b7ff ffffe3c5 802c59c1 f7cae326 18012048
050c085c
3328:f877bca0 9ce3a7c1 37bb83c0 0800a102 3d0d4a0b 00414903 50001202
5270c400
3584:00400363 e3a8c151 e0000010 1b000701 670c484e 091402fe 0c660001
c28a0200
3840:01829b40 0e300020 04015d20 0830841e 508fff9c 34044e18 094cdefc
cb075057
The second virtual segment's size is 16,384 KB. Meanwhile the block bitmap
contains
4096 bits...
Regards,
Gyula