Posts in category zil

# Removing the ZIL

Currently our ZFS pool is using ZIL based on a file created on the rpool which consisting in 2 mirrored SAS drives (15k RPM, 3Gb/s).

With this configuration the pool is able to serve ~8000 synchronized ops per second. Because the this problematic configuration (importing the pool), we have removed the ZIL and the has fallen dramtically to no more than ~100 ops. Therefore the performance of the system is poorly working.

Usage: zilstat.ksh [gMt][-l linecount] [-p poolname] [interval [count]]
-M  # print numbers as megabytes (base 10)
-t  # print timestamp
-p poolname      # only look at poolname
-l linecount    # print header every linecount lines (default=only once)
interval in seconds or "txg" for transaction group commit intervals
note: "txg" only appropriate when -p poolname is used
count will limit the number of intervals reported

examples:
zilstat.ksh # default output, 1 second samples
zilstat.ksh 10  # 10 second samples
zilstat.ksh 10 6    # print 6 x 10 second samples
zilstat.ksh -p rpool    # show ZIL stats for rpool only

output:
[TIME]
N-Bytes    - data bytes written to ZIL over the interval
N-Bytes/s  - data bytes/s written to ZIL over ther interval
N-Max-Rate - maximum data rate during any 1-second sample
B-Bytes    - buffer bytes written to ZIL over the interval
B-Bytes/s  - buffer bytes/s written to ZIL over ther interval
B-Max-Rate - maximum buffer rate during any 1-second sample
ops        - number of synchronous iops per interval
<=4kB      - number of synchronous iops <= 4kBytes per interval
4-32kB     - number of synchronous iops 4-32kBytes per interval
>=32kB     - number of synchronous iops >= 32kBytes per interval
note: data bytes are actual data, total bytes counts buffer size
root@seal.macc.unican.es:~# ./zilstat.ksh -M -p oceano
N-MB     N-MB/s N-Max-Rate       B-MB     B-MB/s B-Max-Rate    ops  <=4kB 4-32kB >=32kB
2          2          2          5          5          5     66     23      0     43
81         81         81        155        155        155   1205     21      0   1184
177        177        177        355        355        355   2734     20      0   2714
66         66         66        134        134        134   1048     25      0   1023
13         13         13         26         26         26    234     33      0    201
0          0          0          0          0          0      1      1      0      0
0          0          0          0          0          0      0      0      0      0
0          0          0          0          0          0      0      0      0      0
0          0          0          0          0          0      0      0      0      0
52         52         52         96         96         96    740      2      0    738
10         10         10         21         21         21    183     20      0    163
5          5          5         12         12         12    122     30      0     92
0          0          0          2          2          2     29     10      0     19
275        275        275        517        517        517   3973     29      0   3944
266        266        266        500        500        500   3833     16      0   3818
12         12         12         25         25         25    214     20      0    194
65         65         65        123        123        123    968     26      0    942
209        209        209        399        399        399   3064     16      0   3048
63         63         63        120        120        120    950     29      0    921
60         60         60        112        112        112    875     21      0    854
2          2          2          7          7          7     87     34      0     53
2          2          2          7          7          7     85     30      0     55
2          2          2          7          7          7     84     30      0     54
60         60         60        113        113        113    888     25      0    863
2          2          2          6          6          6     75     28      0     47
3          3          3          8          8          8     93     32      0     61
60         60         60        115        115        115    909     31      0    878
2          2          2          7          7          7     94     35      4     55
28         28         28         56         56         56    460     31      1    428
35         35         35         65         65         65    538     36      2    500
2          2          2          6          6          6     71     26      0     45
3          3          3          8          8          8     97     34      0     63
61         61         61        114        114        114    904     27      1    876
24         24         24         49         49         49    394     20      0    374
2          2          2          7          7          7     84     30      0     54
3          3          3          8          8          8     98     35      0     63
2          2          2          7          7          7     85     30      0     55
2          2          2          7          7          7     87     32      0     55
540        540        540       1078       1078       1078   8248     23      0   8223
60         60         60        114        114        114    891     21      0    870
.............................................................................................
0          0          0          0          0          0     55     45     10      0
0          0          0          0          0          0     53     50      1      2
0          0          0          0          0          0     56     56      0      0
0          0          0          0          0          0     48     47      0      1
0          0          0          0          0          0     54     48      0      6
0          0          0          0          0          0     68     64      0      4
1          1          1          2          2          2     55     38      0     17
0          0          0          0          0          0     67     67      0      0
0          0          0          0          0          0     43     40      2      1
0          0          0          0          0          0     52     48      2      2
0          0          0          0          0          0     62     49     13      0
0          0          0          0          0          0     49     49      0      0
0          0          0          0          0          0     21     21      0      0
0          0          0          0          0          0     19     11      0      8
0          0          0          0          0          0     25     24      0      1
0          0          0          0          0          0     19     16      3      0
0          0          0          0          0          0     17     17      0      0
0          0          0          0          0          0     19     19      0      0
0          0          0          0          0          0     54     54      0      0
0          0          0          1          1          1     17      9      0      8
0          0          0          1          1          1     46     36      0     10
0          0          0          0          0          0     47     39      2      6
0          0          0          0          0          0     67     66      0      1
0          0          0          0          0          0     18     15      3      0
0          0          0          0          0          0     12     12      0      0
0          0          0          1          1          1     22     14      0      8
0          0          0          0          0          0     22     15      0      7
0          0          0          1          1          1     28     18      2      8
0          0          0          0          0          0     18     11      0      7
0          0          0          0          0          0     16      6      3      7
0          0          0          0          0          0     26     18      2      6
0          0          0          0          0          0     33     33      0      0