Kevin Closson's Blog: Platforms, Databases and Storage

Yes, I admit, sometimes little things make me crabby. Or is it that being crabby makes me easily irritated at small things? I think it’s the former rather than the latter.

Angry Email Makes Me Crabby
I am surprised at how many emails I’ve received from angry Storage Administrators about my position against Fibre Channel. I generally just ask them to not take it so personally. After all, there is more to storage than whatever storage networking protocol any particular server is plumbed with. Anyone who reads my Manly Man series about Fibre Channel will see that I’m just not a big fan of the current misapplication of Fibre Channel technology. As I point out in installment number two in the Manly Man series, Fibre Channel was originally intended to solve the difficulties associated with connecting hundreds (or thousands) of low capacity drives to a small number of large servers. These days it is being used to provide storage connectivity for hundreds of servers to a couple of huge FC storage arrays. And these hundreds of servers have both Ethernet and FC connectivity-overkill, plain and simple.

A lot is changing in the storage world where Oracle is concerned. I hope to come out of the foxhole to blog more about it over the next few months. Well, maybe I should say a few months from now. In the meantime I’ll be making some datacenter visits. I always learn something interesting when I get a chance to do that.

Little Changes Make Me Crabby
Like, for instance, the following example of the change to iostat -x output from RHEL4 to RHEL5. Notice how the rkB/s and wkB/s columns are missing? Yes, it is simple math to divide [rw]sec/s by 2 to get the same data, but there must be at least 42 of you folks that are feeding iostat -x output through some text processing, right? Time to adjust your scripts. Or is it? I wonder how many folks are really diving into OEL5/RHEL5? It seems a conservative IT shop with a functional RHEL4 configuration would most likely stay put. Any readers care to voice their experience with OEL5/RHEL5 adoption? Is it happening? Are folks waiting for their 11g adoption with plans to team that up with a move to OEL5/RHEL5?

 
# uname -r
2.6.18-53.ELsmp
# iostat -x 1 1
Linux 2.6.18-53.el5 (host1)        03/07/2008

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.08    0.00    0.04    0.03    0.00   99.85

Device:         rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz avgqu-sz   await  svctm  %util
cciss/c0d0        0.16    10.38  0.33  0.95    10.55    90.64    79.47     0.02   14.12   0.86   0.11
sda               0.00     0.00  0.00  0.00     0.01     0.00    21.05     0.00    3.18   2.87   0.00
dm-0              0.00     0.00  0.45 11.33    10.47    90.64     8.58     0.39   32.67   0.09   0.11
dm-1              0.00     0.00  0.00  0.00     0.01     0.00     8.00     0.00    5.05   0.51   0.00
cciss/c0d1        0.00     0.00  0.00  0.00     0.01     0.00    10.12     0.00    4.56   2.63   0.00
cciss/c0d2        0.00     0.00  0.00  0.00     0.01     0.00    10.38     0.00    4.30   2.52   0.00
cciss/c0d3        0.00     0.00  0.00  0.00     0.01     0.00    10.38     0.00    6.17   3.35   0.00
cciss/c0d4        0.00     0.00  0.00  0.00     0.01     0.00    10.38     0.00    5.50   3.22   0.00
cciss/c0d5        0.00     0.00  0.00  0.00     0.01     0.00    10.64     0.00    3.38   2.59   0.00
cciss/c0d6        0.00     0.00  0.00  0.00     0.01     0.00    10.64     0.00    4.05   3.31   0.00
cciss/c0d7        0.00     0.00  0.00  0.00     0.01     0.00    10.12     0.00    4.44   2.29   0.00

$ uname -r
2.6.9-34.ELsmp
$ iostat -x 1 1
Linux 2.6.9-34.ELsmp (host2)    03/07/2008

avg-cpu:  %user   %nice    %sys %iowait   %idle
           1.79    0.00    1.28    0.30   96.63

Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm  %util
cciss/c0d0   0.06  11.83  0.14  3.21   23.07  120.39    11.53    60.19    42.77     0.68  201.33   4.60   1.54