Oneiroi's questions

Background:

ssh (client) allows the re-use of active connections via multiplexing ControlPaths ...

Host *
ControlMaster auto
ControlPath /home/username/.ssh/%r@%h:%p

the TL;DR is the first connection will authenticate like any other, subsequent connections will use the controlpath and not perform any additional authentication.

Now my question; is it possible to limit the use of such connections server side ? in the sshd_config.

MaxSessions does not work despite setting to 1 I can connect to a host as many additional times as wanted via the same original connection.

Setting to 0 of course just disabled remote logins entirely.

After a server crash we are having some very strange issues with one particular table reference.

Opting for a restoration from backup the database was dropped and a backup SQL dump loaded, only this fails on the create table for cache_content with the error "table already exists"

mysql> create table cache_content( id int NOT NULL DEFAULT 0 ) ENGINE=InnoDB DEFAULT CHARSET=utf8; ERROR 1005 (HY000): Can't create table '****.cache_content' (errno: -1) mysql> drop table cache_content; ERROR 1051 (42S02): Unknown table 'cache_content'

Oddly the drop table, removed the .frm but not the .ibd file (if it exists), the create table will create the .ibd file but not the .frm file.

I've tried numerous methods for restoration, including importing the dump into a new database (completed without issue), shuttind down mysql and copying the relevant .frm and .ibd files, then using idbconnect to attempt to attach this "known good" version:

... Space id: 1952673645 (0x74636F6D) Next record at offset: 74 TABLE_ID of `****/`.`cache_content` can not be 0 ...

Checking the related tables in information_schema, I can see this is the case and the TABLESPACE has been assigned to 0

mysql> select * from INNODB_SYS_TABLES where `SCHEMA`="*****";
+----------+--------+--------------------------+------+--------+-------+
| TABLE_ID | SCHEMA | NAME                     | FLAG | N_COLS | SPACE |
+----------+--------+--------------------------+------+--------+-------+
...

|    19791 | *****  | cache_content            |    1 |      9 |     0 |
+----------+--------+--------------------------+------+--------+-------+
N rows in set (0.01 sec)

mysql> select * FROM INNODB_SYS_INDEXES where TABLE_ID=19791;
+----------+--------+----------+------+----------+---------+-------+
| INDEX_ID | NAME   | TABLE_ID | TYPE | N_FIELDS | PAGE_NO | SPACE |
+----------+--------+----------+------+----------+---------+-------+
|     7919 | expire |    19791 |    0 |        1 |  311158 |     0 |
+----------+--------+----------+------+----------+---------+-------+
1 row in set (0.00 sec)

Server Version: Percona-Server-server-55-5.5.27-rel28.0.291.rhel6.x86_64

Now I'm fairly sure from the reading I've done into that removing ibdata1 ib_logfile* may be the only way of cleaning up this "ghost" reference.

My Question: Is there any way to clean up these ghost references to allow the table to be restored from backup?

I have been reviewing XtraDB clustering and produced a P.o.C. environment on Openstack using 4 instances, which has fallen over during my resilience testing.

Per the pxc documentation: http://www.percona.com/doc/percona-xtradb-cluster/howtos/virt_sandbox.html which covers a 3 node install I opted for a 4th.

1. Initial setup complete data loading tests passed, with all nodes being updates synchronously using a 1.6GB test sql file to load a database.
2. Failiure and restore of nodes commenced, this test entailed stoping the mysql service on a node, creating and subsequently dropping a database to test surviving node replication, and starting of the downed node to resync.
   1. This worked fine for nodes 4,3,2.
   2. Node1 which per the pxc documents is essentially a controller, would not rejoin the cluster.

So my questions are as follows:

1. How to return a controller node to service if surviving nodes have since had data written to them
2. Using 4 nodes as a reference, is there a way to remove this single point of failure in node1? (if a surviving node restarts with the controller (node1) down/out of sync, that node will also fail).

I have a very odd issue with our cisco firewall,

If on our osx machines we run the following to disable window scaling support:

sudo sysctl -w net.inet.tcp.rfc1323=0

We see near 40% improvement in download speeds (tested using varying linux iso image mirrors).

If I sit my machine directly onto the outside modem (Manually setting up an external ip adress within the range etc), the bandwidth remains constant with rfc1323 enabled and disabled, so it has to be the cisco.

Something else to note:

• None of our linux devices suffer this problem

Has anyone come across this issue before? I seem to find some vague references in old mailing lists detailing PIX workarounds which are no longer applicable to cisco ios.

Thanks in advance.

I have a HP DL180 G6 with a P410 raid controller.

Presently this runs using 4x 1TB Samsung Spinpoint SATA drives, in a RAID10 configuration using default settings.

I am about to add a backplane to increase the drive capacity from 4 to 12 drives, and I plan to install 4 more 1TB SATA Drives.

• The drives are matched and have close serial numbers (They arrived together in the Manufacturers pallet).
• Model HD103UJ 1000GB/7200rpm/32M
• Rated for 3GB/s

I will also be installing RHEL 6.1 x86_64.

My question is what would be the optimal RAID settings (stripe etc.) for this configuration?

To recap:

• 8x Model HD103UJ 1000GB/7200rpm/32M
• Rated for 3GB/s
• RAID 10 configuration.

Thanks in advance.

Update for role:

• Server is to become an iscsi target for an internal openstack deployment currently underway. (Glance)
• Will also provide virtualisation through KVM

I am trying to setup a transparent proxy between eth0 and lo,

The reason being during DNS propagation services are being tunneled over a SSH connection between the old and new servers, on the "old" server this is fine for anything running locally connecting to localhost:

However for anything hitting the external address of the "old server" the service is not forward as the ssh tunnel only listens for connections to localhost (lo).

Current setup:

Old server --> SSH Tunnel --> New server

What needs to happen

Client connection (i.e. tcp 8081) --> Old Server --> SSH Tunnel --> New server

I am trying multiple variations on ip table rules, setting -L <service port>:0.0.0.0:<service port> does not listen on all interfaces only on lo.

The solution must come from iptables alone, there is no time to deploy squid / another proxy service.

So in summary.

• Assume tcp 8081, is tunneled over SSH connection
• I need this to work from the eth0 bound address

Thanks In Advance

We have been using awstats for some time now to parse our apache server logs into a format for the billing dept.

A set of custom python script are in use to generate the merge logs based on those passed from each of the servers in the hosting cluster/farm.

The issue I am currently facing is that our logs have grown considerably for certain projects, some generating ~30GB/day in uncompressed logs. awstats is not the most memory efficient of parsers, and will use upward of 1GB of memory to process these logs, (by comparison a python script + regex of mine will with in 450kb of memory).

What I need is a replacement to awstats that can handle large logfiles on a fairly basis and produce a "billing friendly" output.

Stats should include, bandwidth, unique visitos, vists per unique pages served etc ...

Idealy this should also allow us to import the historical Awstats data (which is currently in text files).

So in summary my question is, is there any software available to do this?

OS is centOS 5.5 x64, rpm's are as follows:

• tomcat5-jsp-2.0-api-5.5.23-0jpp.9.el5_5
• tomcat5-common-lib-5.5.23-0jpp.9.el5_5
• tomcat5-servlet-2.4-api-5.5.23-0jpp.9.el5_5
• tomcat5-server-lib-5.5.23-0jpp.9.el5_5
• tomcat5-5.5.23-0jpp.9.el5_5
• tomcat5-jasper-5.5.23-0jpp.9.el5_5

telnet localhost 8080
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
GET / HTTP/1.0
Host: localhost

HTTP/1.1 400 Bad Request
Server: Apache-Coyote/1.1
Date: Thu, 16 Sep 2010 15:06:21 GMT
Connection: close

alternatives --display java output:

alternatives --display java
java - status is manual.
 link currently points to /usr/lib/jvm/jre1.6.0_21/bin/java
/usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java - priority 16000
 slave keytool: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/keytool
 slave orbd: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/orbd
 slave pack200: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/pack200
 slave rmid: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/rmid
 slave rmiregistry: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/rmiregistry
 slave servertool: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/servertool
 slave tnameserv: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/tnameserv
 slave unpack200: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/unpack200
 slave jre_exports: /usr/lib/jvm-exports/jre-1.6.0-openjdk.x86_64
 slave jre: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64
 slave java.1.gz: /usr/share/man/man1/java-java-1.6.0-openjdk.1.gz
 slave keytool.1.gz: /usr/share/man/man1/keytool-java-1.6.0-openjdk.1.gz
 slave orbd.1.gz: /usr/share/man/man1/orbd-java-1.6.0-openjdk.1.gz
 slave pack200.1.gz: /usr/share/man/man1/pack200-java-1.6.0-openjdk.1.gz
 slave rmid.1.gz: /usr/share/man/man1/rmid-java-1.6.0-openjdk.1.gz
 slave rmiregistry.1.gz: /usr/share/man/man1/rmiregistry-java-1.6.0-openjdk.1.gz
 slave servertool.1.gz: /usr/share/man/man1/servertool-java-1.6.0-openjdk.1.gz
 slave tnameserv.1.gz: /usr/share/man/man1/tnameserv-java-1.6.0-openjdk.1.gz
 slave unpack200.1.gz: /usr/share/man/man1/unpack200-java-1.6.0-openjdk.1.gz
/usr/lib/jvm/jre-1.4.2-gcj/bin/java - priority 1420
 slave keytool: /usr/lib/jvm/jre-1.4.2-gcj/bin/keytool
 slave orbd: (null)
 slave pack200: (null)
 slave rmid: (null)
 slave rmiregistry: /usr/lib/jvm/jre-1.4.2-gcj/bin/rmiregistry
 slave servertool: (null)
 slave tnameserv: (null)
 slave unpack200: (null)
 slave jre_exports: /usr/lib/jvm-exports/jre-1.4.2-gcj
 slave jre: /usr/lib/jvm/jre-1.4.2-gcj
 slave java.1.gz: (null)
 slave keytool.1.gz: (null)
 slave orbd.1.gz: (null)
 slave pack200.1.gz: (null)
 slave rmid.1.gz: (null)
 slave rmiregistry.1.gz: (null)
 slave servertool.1.gz: (null)
 slave tnameserv.1.gz: (null)
 slave unpack200.1.gz: (null)
/usr/lib/jvm/jre1.6.0_21/bin/java - priority 2
 slave keytool: (null)
 slave orbd: (null)
 slave pack200: (null)
 slave rmid: (null)
 slave rmiregistry: (null)
 slave servertool: (null)
 slave tnameserv: (null)
 slave unpack200: (null)
 slave jre_exports: (null)
 slave jre: (null)
 slave java.1.gz: (null)
 slave keytool.1.gz: (null)
 slave orbd.1.gz: (null)
 slave pack200.1.gz: (null)
 slave rmid.1.gz: (null)
 slave rmiregistry.1.gz: (null)
 slave servertool.1.gz: (null)
 slave tnameserv.1.gz: (null)
 slave unpack200.1.gz: (null)
Current `best' version is /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java.

Same occurs trying HTTP/1.1, and I am at a complete loss as to why.

I have an issue this morning where I want to be able to assign multiple ip addresses to the inside interface to facilitate an ip range migration for an office.

Namely from a 192.168.1.x range to the new range, with the minimum of interruption for those working in the office.

(New DHCP leases will use the new range, whilst those still on the 192.168.1.x range can continue to work until their lease is renewed).

However I can not for the life of me figure out how to achieve this, trying to create multiple interfaces for the job leads to complaints about the license only allowing 2 active interfaces.

Any suggestions?

thanks in advance.

I find myself vexed this afternoon, I have recently taken on some RHEL5 servers on board and have found something rather peculiar, most likely I am missing something glaringly obvious so please let me know what is going on here.

I place this in /etc/snmp/snmpd.conf and restart snmpd

rocommunity somefictionalname xxx.xxx.xxx.xxx

Now on all my CentOS 5 servers this works just fine, see the following tcp dump of a working transaction:

14:51:54.108322 IP client.39690 > server.snmp:  GetNextRequest(25)  
14:51:54.108836 IP server.snmp > client.39690:  GetResponse(120)  system.sysDescr.0=[|snmp]
14:51:54.109211 IP client.39690 > server.snmp:  GetNextRequest(28)  system.sysDescr.0
14:51:54.109516 IP server.snmp > client.39690:  GetResponse(38)  system.sysObjectID.0=E:8072.3.2.10
14:51:54.109762 IP client.39690 > server.snmp:  GetNextRequest(28)  system.sysObjectID.0

Now the from the RHEL5 box using the same configuration line.

14:55:37.015363 IP client.34551 > server.snmp:  GetNextRequest(25)  
14:55:38.016614 IP client.34551 > server.snmp:  GetNextRequest(25)  
14:55:39.016851 IP client.34551 > server.snmp:  GetNextRequest(25)  
14:55:40.018476 IP client.34551 > server.snmp:  GetNextRequest(25)  
14:55:41.019392 IP client.34551 > server.snmp:  GetNextRequest(25)  
14:55:42.019544 IP client.34551 > server.snmp:  GetNextRequest(25)

On the RHEL5 box I see the following in /var/log/messages

snmpd[pid]: Connection from UDP: [client]:34551 REFUSED

But I am at a loss at to why ... I'll keep looking into this but please feel free to point me in the right direction.

Cheers

Oneiroi