http://new.watters.ws News Feed http://new.watters.ws/view/article/186 2013-05-01 16:06:00 <p>If you need admin access to a wordpress install you can easily create a new admin user by running a few SQL commands on the database. This has been tested and verified to work on Wordpress 3.5.</p> <p>To do this you will first need to identify what database the site is actually using. Check wp-config.php for the database name and mysql host info. Once you have that connect to mysql and run the following statements.</p> <p class="code">INSERT INTO wp_users (user_login,user_pass,user_email,user_registered,user_status) VALUES("user_name",md5('password'),"username@example.com",NOW(),0);</p> <p>Find user ID from wp_users table:</p> <pre class="code">SET @user_id = (SELECT ID FROM wp_users where user_login = 'user_name'); INSERT INTO wp_usermeta (user_id,meta_key,meta_value) VALUES (@user_id,"wp_user_level","10"); INSERT INTO wp_usermeta (user_id,meta_key,meta_value) VALUES (@user_id,"wp_capabilities",'a:1:{s:13:"administrator";s:1:"1";}'); </pre> http://new.watters.ws/view/article/185 2013-04-11 13:56:00 <p>After reading about various cluster file systems I decided to set up a small cluster running Lustre using Storm VPS instances. All nodes have the same hardware configuration and use a 50 GB SAN volume connected through iSCSI as the lustre block device. Specs are as follows.</p> <pre> Node configuration: OS: CentOS 6.3 x86_64 Kernel: 2.6.32-279.19.1.el6_lustre.x86_64 RAM: 3556 MB (Storm 4 GB) Primary Disk: 300 GB virtual disk Secondary Disk (iscsi): 50 GB SAN volume CPU: Two Intel(R) Xeon(R) CPU E3-1220 V2 @ 3.10GHz cores Lustre configuration: 1 management server, 1 metadata server, 1 object storage server. LNET was configured to use a private network interface. </pre> <p>Disk performance was tested with the sgpdd_survey script from the Lustre IOkit. Write speed appears to average around 35-40 MB/s.</p> <pre> Wed Apr 10 10:29:39 EDT 2013 sgpdd-survey on /dev/sda from oss1.watters.ws total_size 8388608K rsz 1024 crg 1 thr 1 write 49.32 MB/s 1 x 49.32 = 49.32 MB/s read 68.15 MB/s 1 x 68.15 = 68.15 MB/s total_size 8388608K rsz 1024 crg 1 thr 2 write 77.15 MB/s 1 x 77.15 = 77.15 MB/s read 92.85 MB/s 1 x 92.85 = 92.85 MB/s total_size 8388608K rsz 1024 crg 1 thr 8 write 36.15 MB/s 1 x 36.14 = 36.14 MB/s read 94.08 MB/s 1 x 94.09 = 94.09 MB/s total_size 8388608K rsz 1024 crg 1 thr 16 write 35.84 MB/s 1 x 35.85 = 35.85 MB/s read 101.59 MB/s 1 x 101.59 = 101.59 MB/s total_size 8388608K rsz 1024 crg 2 thr 2 write 35.34 MB/s 2 x 17.67 = 35.34 MB/s read 67.38 MB/s 2 x 33.69 = 67.39 MB/s total_size 8388608K rsz 1024 crg 2 thr 4 write 39.09 MB/s 2 x 19.55 = 39.10 MB/s read 79.20 MB/s 2 x 39.60 = 79.19 MB/s total_size 8388608K rsz 1024 crg 2 thr 8 write 40.40 MB/s 2 x 20.20 = 40.40 MB/s read 98.16 MB/s 2 x 49.09 = 98.17 MB/s total_size 8388608K rsz 1024 crg 2 thr 16 write 37.73 MB/s 2 x 18.86 = 37.73 MB/s read 99.31 MB/s 2 x 49.66 = 99.32 MB/s total_size 8388608K rsz 1024 crg 2 thr 32 write 38.08 MB/s 2 x 19.04 = 38.07 MB/s read 97.30 MB/s 2 x 48.66 = 97.31 MB/s total_size 8388608K rsz 1024 crg 4 thr 4 write 38.38 MB/s 4 x 9.59 = 38.38 MB/s read 98.17 MB/s 4 x 24.55 = 98.19 MB/s total_size 8388608K rsz 1024 crg 4 thr 8 write 38.25 MB/s 4 x 9.57 = 38.26 MB/s read 100.06 MB/s 4 x 25.01 = 100.06 MB/s total_size 8388608K rsz 1024 crg 4 thr 16 write 39.42 MB/s 4 x 9.85 = 39.41 MB/s read 99.96 MB/s 4 x 25.00 = 99.98 MB/s total_size 8388608K rsz 1024 crg 4 thr 32 write 39.43 MB/s 4 x 9.86 = 39.44 MB/s read 99.93 MB/s 4 x 24.99 = 99.95 MB/s total_size 8388608K rsz 1024 crg 4 thr 64 write 38.22 MB/s 4 x 9.56 = 38.22 MB/s read 97.80 MB/s 4 x 24.45 = 97.81 MB/s total_size 8388608K rsz 1024 crg 8 thr 8 write 38.73 MB/s 8 x 4.84 = 38.76 MB/s read 87.71 MB/s 8 x 10.97 = 87.74 MB/s total_size 8388608K rsz 1024 crg 8 thr 16 write 39.70 MB/s 8 x 4.96 = 39.67 MB/s read 81.09 MB/s 8 x 10.14 = 81.10 MB/s total_size 8388608K rsz 1024 crg 8 thr 32 write 43.40 MB/s 8 x 5.43 = 43.41 MB/s read 81.21 MB/s 8 x 10.16 = 81.25 MB/s total_size 8388608K rsz 1024 crg 8 thr 64 write 38.88 MB/s 8 x 4.86 = 38.91 MB/s read 67.10 MB/s 8 x 8.39 = 67.14 MB/s total_size 8388608K rsz 1024 crg 8 thr 128 write 42.19 MB/s 8 x 5.27 = 42.19 MB/s read 65.92 MB/s 8 x 8.24 = 65.92 MB/s </pre> <p>IOPS performance was tested using <i>iozone</i>, here are the results.</p> <pre> OPS Mode. Output is in operations per second. Include fsync in write timing No retest option selected Record Size 4 KB File size set to 4194304 KB Command line used: iozone -l 32 -O -i 0 -i 1 -i 2 -e -+n -r 4K -s 4G Time Resolution = 0.000001 seconds. Processor cache size set to 1024 Kbytes. Processor cache line size set to 32 bytes. File stride size set to 17 * record size. Min process = 32 Max process = 32 Throughput test with 32 processes Each process writes a 4194304 Kbyte file in 4 Kbyte records Children see throughput for 32 initial writers = 27764.87 ops/sec Parent sees throughput for 32 initial writers = 26692.16 ops/sec Min throughput per process = 840.07 ops/sec Max throughput per process = 903.35 ops/sec Avg throughput per process = 867.65 ops/sec Min xfer = 975918.00 ops Children see throughput for 32 readers = 26758.37 ops/sec Parent sees throughput for 32 readers = 26755.12 ops/sec Min throughput per process = 448.79 ops/sec Max throughput per process = 1372.74 ops/sec Avg throughput per process = 836.20 ops/sec Min xfer = 342845.00 ops </pre> <p>As you can see lustre is a relatively high performance file system and is easily scalable to store petabytes of data. Adding more space is as simple as building a new object server and running mkfs.lustre.</p> http://new.watters.ws/view/article/184 2013-04-10 13:35:00 <p>If you want to set up a yum repo you can easily mirror an existing site using wget. To do this you will need to run this command.</p> <pre> wget --mirror -np --no-host-directories -A rpm,srpm http://downloads.whamcloud.com/public/lustre/latest-maintenance-release/ </pre> <p>In this case we are mirroring the lustre rpm repo.</p> <p>After the files are downloaded you can run the <b>createrepo</b> command to create yum metadata.</p> http://new.watters.ws/view/article/181 2012-04-24 10:13:00 <p>If you work on a lot of servers and do a lot of reinstalls you will see the following error often.</p> <pre> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is a8:6a:60:5a:48:64:ac:90:33:b9:f2:7c:be:56:92:81. Please contact your system administrator. Add correct host key in /var/root/.ssh/known_hosts to get rid of this message. Offending key in /root/.ssh/known_hosts:9948 RSA host key for host.example.com has changed and you have requested strict checking. Host key verification failed. </pre> <p>To save some time you can quickly remove the old host key with a single sed command:</p> <pre>sed -i '9948d' .ssh/known_hosts</pre> http://new.watters.ws/view/article/180 2012-04-02 21:57:00 <p>After upgrading my netbook kernel to the latest stable version available on backports.org I soon discovered that my wireless interface no longer worked. Trying to rebuild the module resulted in the following error:</p> <pre> /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c: In function ‘_wl_set_multicast_list’: /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1435: error: ‘struct net_device’ has no member named ‘mc_list’ /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1435: error: ‘struct net_device’ has no member named ‘mc_count’ /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1436: error: dereferencing pointer to incomplete type /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1442: error: dereferencing pointer to incomplete type make[4]: *** [/usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.o] Error 1 make[3]: *** [_module_/usr/src/modules/broadcom-sta/amd64] Error 2 make[2]: *** [sub-make] Error 2 make[1]: *** [all] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-0.bpo.2-amd64' make: *** [all] Error 2 root@netbook:/usr/src/modules/broadcom-sta/amd64# run "make API=WEXT" bash: run: command not found root@netbook:/usr/src/modules/broadcom-sta/amd64# "make API=WEXT" bash: make API=WEXT: command not found root@netbook:/usr/src/modules/broadcom-sta/amd64# make API=WEXT KBUILD_NOPEDANTIC=1 make -C /lib/modules/`uname -r`/build M=`pwd` make[1]: Entering directory `/usr/src/linux-headers-3.2.0-0.bpo.2-amd64' CC [M] /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.o /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c: In function ‘_wl_set_multicast_list’: /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1435: error: ‘struct net_device’ has no member named ‘mc_list’ /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1435: error: ‘struct net_device’ has no member named ‘mc_count’ /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1436: error: dereferencing pointer to incomplete type /usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.c:1442: error: dereferencing pointer to incomplete type make[4]: *** [/usr/src/modules/broadcom-sta/amd64/src/wl/sys/wl_linux.o] Error 1 make[3]: *** [_module_/usr/src/modules/broadcom-sta/amd64] Error 2 make[2]: *** [sub-make] Error 2 make[1]: *** [all] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-3.2.0-0.bpo.2-amd64' make: *** [all] Error 2 </pre> <p>A bit of googling lead me to a few patches that helped solve the issue. Here is a unified diff of my changes which should allow you to cleanly build and install the wl module using module-assistant.</p> <p>http://www.watters.ws/broadcom_bcm4313_linux3.2.patch</p> <p>One thing to note is that the source code needs to be patched BEFORE you run m-a, i.e. cd to /usr/src/modules/broadcom_sta/amd64/src/wl/sys and run patch the patch from there.</p> <p>I hope that somebody will find this useful.</p> http://new.watters.ws/view/article/177 2009-11-26 13:16:12 <p>Hard to believe it's been a year since I posted this.</p> <pre> ,+*^^*+___+++_ ,*^^^^ ) _+* ^**+_ +^ _ _++*+_+++_, ) _+^^*+_ ( ,+*^ ^ \+_ ) { ) ( ,( ,_+--+--, ^) ^ { (@) } f ,( ,+-^ __*_*_ ^^\_ ^\ ) {:;-/ (_+*-+^^^^^+*+*<_ _++_)_ ) ) / ( / ( ( ,___ ^*+_+* ) < < U _/ ) *--< ) ^\-----++__) ) ) ) ( ) _(^)^^)) ) )\^^^^^))^*+/ / / ( / (_))_^)) ) ) ))^^^^^))^^^)__/ +^^ ( ,/ (^))^)) ) ) ))^^^^^^^))^^) _) *+__+* (_))^) ) ) ))^^^^^^))^^^^^)____*^ \ \_)^)_)) ))^^^^^^^^^^))^^^^) (_ ^\__^^^^^^^^^^^^))^^^^^^^) ^\___ ^\__^^^^^^))^^^^^^^^) ^^^^^\uuu/^^\uuu/^^^^\^\^\^\^\^\^\^ ___) >____) >___ ^\_\_\_\_\_\_\) ^^^//\_^^//\_^ ^(\_\_\_\) ^^^ ^^ ^^^ ^^ # # ## ##### ##### # # # # # # # # # # # # ###### # # # # # # # # # ###### ##### ##### # # # # # # # # # # # # # # # ##### # # ## # # # # #### # # # # # ## # # # # # ###### # # # # # #### #### # # # ###### # # # # # # # # # # # # ## # # # # # # # # # # # # # #### #### # # # # # # #### # # # # # # ## # # # # # # # # # # # # # ### # # # # # # # # ### # # # # # # # ## # # #### # ## # # # #### </pre> <p>Download the script here: http://linuxshellaccount.blogspot.com/2008/11/happy-thanksgiving-unixlinux-ascii-art.html</p> http://new.watters.ws/view/article/176 2009-09-14 00:38:05 <p>If you're sick of the update notifier bugging you on your Ubuntu desktop you can easily set up a cron job to automatically take care of things.</p> <pre class='code'>sudo crontab -e 0 5 * * * apt-get -y upgrade </pre> <p>Change the time to whenever you want.</p> http://new.watters.ws/view/article/172 2009-06-10 18:19:19 <p>I've been updating the code for my site a bit to make things load a bit faster and one of the things I fixed was the random query generator.</p> <p class="code">SELECT quote, name FROM quotes ORDER BY RANDOM() LIMIT 1</p> <p>The query above works great for small tables but consider the issue when you have a table with millions of rows, the server must read every row, sort them, and then throw out all the results but the first. This takes a lot of CPU time and is slow, the optimal solution is to use create a sequence as the primary key and then generate a random number using that. For example:</p> <p class="code">idx = select last_value FROM quotes_idx_seq</p> <p class="code">SELECT quote_text, name FROM quotes WHERE quote_id = '%s' %idx</p> <p>It requires two queries instead of one but there is much less disk I/O required.</p> http://new.watters.ws/view/article/171 2009-06-05 14:51:43 <p class="code">Directory '/var/run/screen' must have mode 777.</p> <p>This is a fairly common error I've been seeing lately and the solution is quite simple.</p> <p class="code">chmod g+s /usr/bin/screen</p> http://new.watters.ws/view/article/169 2009-03-02 22:39:08 <p>I originally posted about this back in October when this whole crisis started but as with all things econ there is a time lag between cause and effect. I have stated many times that I expect the DJIA to return to around the 5000 level and now many economists expect it to go even lower than that.</p> <p>I'm not trying to spread gloom and no matter what happens I think we'll survive, humanity has made it through far worse times. One things for sure, the days of zero down, interest only loans are OVER.</p> <p>Here's the latest graph I've made reflecting recent closing values.<img src="images/dow.png" border="0"></p>