User1's questions

I have a RHEL6 box with php and apache. I want to increase my upload limit to 20MB. I changed upload_max_filesize parameter in /etc/php.ini. I restarted the httpd service. But when I load the php_info() page, I still see a upload_max_filesize of 2MB (the default value).

I have SELinux enabled, but I don't see any recent "avc" entries in /var/log/audit/audit.log (though I have some from a few days ago). Is there another .ini file I must change? How can I get an upload_max_filesize value to stick?

I have a heavy postgres query. It takes over ten minutes to run. I'd like to upgrade my hardware to get it run faster. I think more RAM will help, but my motherboard is full so I'll need a whole new motherboard. I don't want to invest unless I know I'll get better results. Here's what I see in iotop:

Total DISK READ:      46.81 M/s | Total DISK WRITE:       0.00 B/s
  TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                                                                                                                                               
   27 be/4 root        0.00 B/s    0.00 B/s  0.00 % 99.99 % [kswapd0]
 2514 be/4 postgres   46.81 M/s    2.45 M/s  0.00 % 18.36 % postgres: postgres db1 127.0.0.1(55328) SELECT
    1 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % init
    2 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kthreadd]
    3 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [ksoftirqd/0]
    4 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/0:0]
    5 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/u:0]
    6 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/0]
    7 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [watchdog/0]
    8 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/1]
    9 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/1:0]
   10 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [ksoftirqd/1]

Notice how the kswapd0 is hitting the hard drive the most (99.99% IO). However, the DISK READ and DISK WRITE and SWAPIN of kswap0 are all zero. What is kswap0 doing? Is it really hitting my hard drive? Would adding more RAM to this system help at all?

I have two machines:

Machine #1:

• Desktop
• Intel E5200 CPU (2.5Ghz)
• 2GB RAM (DDR2)
• Spinning hard drive (OS) and SSD Hard drive (data)

Machine #2:

• Laptop
• AMD E-300 (1.3GHz) CPU
• 8GB RAM (DDR3)
• Spinning hard drive

Both machines are running Ubuntu 11 and Postgres 9.1.

I have a large Postgres database (>100GB) and am running an advanced query. As I watch the query, all I see is 100% CPU on both machines..only one core seems to be used. iotop shows very little hard drive activity (maybe 1MB/s bursts).

Machine #1 finishes in 20 minutes. Machine #2 is still running after 5 hours. I figured that Machine #2 would be about half the speed of Machine #1 (1.3Ghz vs 2.5 Ghz)..maybe a little better due to more RAM.

I ran this as a quick test to see if buying more RAM would make a huge difference on Machine #1, but it seems that CPU plays a much bigger role. Am I right or is there something else going on?

A few questions:

1. What factors on Machine #2 are making it so slow?
2. Could it be that the SSD is making a huge difference but I can't see it in iotop?
3. Given a limited budget..which upgrades could I do to Machine #2 to make it even faster? In particular is RAM or CPU a better investment?

I have a site with wireless (192.168.0.0) and a wired network (192.168.1.0). Each network has its own DHCP server and other such infrastucture. There is an Ubuntu Linux machine that has a connection to both networks. Can I somehow configure this Linux machine to allow two computers on these separate networks to communicate?

I heard that bridges do not work with wireless hosts. I think I want a NAT but most documentation I have found tries to connect some isolated network to the Internet. I do not need that in this case. I just need one computer from 192.168.0.0 to transfer files to a computer in 192.168.1.0. The must be some simple answer.

Which characters are invalid for an ext3 filename? I imagine that at least / is an invalid character and probably \0. Is there an official list somewhere?

I'm not exactly sure where to look for this information, so please tell me where you found it.

I just installed a new gigabit network interface card (NIC) in Linux. How do I tell if it is really set to gigabit speeds? I see ethtool has an option to set the speed, but I can't seem to figure out how to report its current speed.

Yes, yes I know there are no real passwords or even hashes in that file on modern systems. However, I am quite curious if this is a good, easy way to totally lock down a system from everyone and what would break first. I don't have a spare system, but it sure sounds like a fun experiment. Has anyone tried this?

I frequently use ssh within screen to connect to a set of machines. It would be ideal to have the caption line show information about the server that I am ssh'd into (eg machinename, uptime and info from vmstat).

I noticed that the backtick screen command only seems to run where screen is run, it doesn't execute on the remote machine. Is there an easy way to get backtick to run the command on whatever machine is currently ssh'd?

If I open Cygwin in rxvt, running wmic does not show the expected wmic:root\cli> prompt. If I execute C:\cygwin\bin\bash.exe from cmd.exe, running wmic inside bash.exe returns the expected prompt. Why?

I have the environment variable CYGWIN set to ntsec tty. I can echo "hello" with a response and everything else seems happy. It's just when I run wmic and a few other Windows applications that have a prompt, the prompt never appears.

EventViewer in Windows has the ability to export a log to a CSV file. I would like to automatically make a backup of that log in that format (as has been done manually in the past few years). It's a standalone system that will typically not have network connectivity, so log centralization tools probably won't work.

I noticed a wmic NTEVENT command, but can't seem to get to export to CSV. Here's an example: NTEVENT WHERE "LogFile='application' AND TimeGenerated > '20100709173000.000000-300'"

Can I get that to output to a CSV file?

I need to make a tunnel from Linux to my Windows 7 machine. I have been able to get it to work with Cygwin, but it's not possible to remove the tunnel later.

To create the tunnel, I type:

ssh -f -N -L 5001:localhost:3306 target

The tunnel goes up with no issues. However, there doesn't seem to be a way to kill it. TCPView shows the process as <non-existent>, but does give a ProcessID. The ProcessID has already terminated and if I right-click and select "Close Connection". Nothing happens.

Short of a reboot or network enable/disable, what can I do to get rid of this tunnel?

When looking at the permissions of an XP machine, I noticed that "Power Users" have permissions on a LOT of key files. I do not want to use "Power Users" at all, but Windows does not let me delete that group. Is there an easy way to remove ALL file permissions for this group?

If I installed Postgres on coLinux, would it be as fast as installing Postgres natively on Windows? How much of a difference in the coLinux instance would there be if the data were stored in a mounted NTFS drive as opposed to an ext2 file on top of NTFS?

I'm interested in accessing my IMAP accounts offline. I found that maildirs are a simple way to make it work. I found that [offlineimap] takes care of almost everything in making the IMAP->maildir sync happen. Then, I can open the account in Mutt or Wanderlust client.

One major problem, maildirs use colons in their filenames. Windows doesn't allow colons. I tried mount -f -s -b -o managed "d:/tmp/mail" "/home/of/mail" in Cygwin, but doing an echo test > /home/of/mail/test:file didn't work

I'm thinking about ext2fs, but I need an ext2 partition somewhere. Can I make a file into a partition somehow? I don't want to start modifying my hard drive's partition table. Besides, does anyone know if ext2fs will support colons in filenames?

There's a very highly rated application for defect management called Redmine. It's written in Ruby. I was able to get it working following their instructions. However, I would like to run the application as a service that starts automatically every time the server reboots. How do you go about adding a Ruby website as a Linux service?

I just created a new MySQL data directory using mysql_install_db:

$mysql_install_db --datadir=/home/user1/opt/mysqld/data/
Installing MySQL system tables...
091123 10:51:54 [Warning] One can only use the --user switch if running as root

OK
Filling help tables...
091123 10:51:54 [Warning] One can only use the --user switch if running as root

OK

To start mysqld at boot time you have to copy
support-files/mysql.server to the right place for your system

PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
To do so, start the server, then issue the following commands:
/usr/bin/mysqladmin -u root password 'new-password'
/usr/bin/mysqladmin -u root -h machine1 password 'new-password'
See the manual for more instructions.
You can start the MySQL daemon with:
cd /usr ; /usr/bin/mysqld_safe &

You can test the MySQL daemon with mysql-test-run.pl
cd mysql-test ; perl mysql-test-run.pl

Please report any problems with the /usr/bin/mysqlbug script!

The latest information about MySQL is available on the web at
http://www.mysql.com
Support MySQL by buying support/licenses at http://shop.mysql.com

I ran mysqld_safe to start the instance, but mysql will not connect. I can run mysqld with --skip-grant, but it won't let me set new privileges. How do I kickstart the permissions on a new MySQL instance?

$ps aux|grep mysql

root      2602  0.0  0.0  87076  1308 ?        S    Nov22   0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid
mysql     2662  0.0  0.2 190676 23732 ?        Sl   Nov22   0:22 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock
user1    18954  0.0  0.0  84984  1224 pts/4    S+   11:36   0:00 /bin/sh /usr/bin/mysqld_safe --defaults-file=my.cnf
user1    18980  0.0  0.2 190160 22860 pts/4    Sl+  11:36   0:00 /usr/libexec/mysqld --defaults-file=my.cnf --basedir=/usr --datadir=/home/user1/opt/mysqld/data --pid-file=/home/user1/opt/mysqld/mysqld.pid --skip-external-locking --port=3307 --socket=/home/user1/opt/mysqld/mysql.sock
user1    20148  0.0  0.0  82236   756 pts/2    S+   12:15   0:00 grep mysql

netstat -lnp|grep mysql

tcp        0      0 0.0.0.0:3307                0.0.0.0:*                   LISTEN      18980/mysqld
unix  2      [ ACC ]     STREAM     LISTENING     153644 18980/mysqld        /home/user1/opt/mysqld/mysql.sock
unix  2      [ ACC ]     STREAM     LISTENING     8193   -                   /var/lib/mysql/mysql.sock

Edit: There are two instances of MySQL. I want the one on port 3307. mysqld_safe is being run as user1 not root with this command: mysqld_safe --defaults-file=my.cnf

I already have an instance of MySQL running a production system. I want to use the same machine to do other MySQL stuff without touching the other instance. I copied my.cnf and rerouted everything (port,datadir,etc). Running mysqld_safe using the new config stopped right away. I looked at the logs. Everything looked good until this line:

[ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

So, I run mysql_install_db --datadir=my/new/db and get this:

Installing MySQL system tables...
091120 19:01:24 [ERROR] /usr/libexec/mysqld: unknown option '-e'

Installation of system tables failed!

Examine the logs in opt/mysqld/data/ for more information.
You can try to start the mysqld daemon with:
/usr/libexec/mysqld --skip-grant &
and use the command line tool
/usr/bin/mysql to connect to the mysql
database and look at the grant tables:

shell> /usr/bin/mysql -u root mysql
mysql> show tables

Try 'mysqld --help' if you have problems with paths. Using --log
gives you a log in opt/mysqld/data/ that may be helpful.

The latest information about MySQL is available on the web at
http://www.mysql.com
Please consult the MySQL manual section: 'Problems running mysql_install_db',
and the manual section that describes problems on your OS.
Another information source is the MySQL email archive.
Please check all of the above before mailing us!
And if you do mail us, you MUST use the /usr/bin/mysqlbug script!

I'm not giving a -e option on my call. What do I do?

EDIT: I followed the instructions in the error and get access denied for 'root'@'localhost'. The server is running and the appropriate port is listening. How do I log-in after doing a skip-grant?