When stress testing our loadbalancer, i was unable to get more than 20 reliable ssh connections. The following error would be reported.
ssh_exchange_identification: Connection closed by remote host
The resolution for this is quite simple.
Edit the /etc/ssh/sshd_config file and increase the MaxStartups. On my server i set this to 200.
Edit /etc/sysctrl.conf and add the following line:
net.core.netdev_max_backlog = 3000
Then apply this change:
# sysctl -p
auth sufficient pam_krb5.so try_first_pass
auth sufficient pam_unix.so shadow nullok try_first_pass
account required pam_unix.so broken_shadow
account [default=bad success=ok user_unknown=ignore] pam_krb5.so
- edit the .vmx file and add the following line
uuid.action = "keep"
- set the virtual machine to power off when vmware is stopped. Do not set this to "suspend" or it will not restart on the backup machine.
DirectoryIndex default.rsp index.html
Here's how to set up field validation based on dynamic values from another table.
Using the products.dbf table from the southwind sample database, validation can be added to the categoryid field to ensure it matches an existing categoryid from the categories.dbf table.
open database southwindThe rlookup() function checks whether an expression exists in the index (master or specified) of the specified table . An attempt to update categoryid with a value not in the list will give an error: Validation on field 'CATEGORYID' failed.
alter table products add constraint;
(categoryid set check rlookup(products.categoryid,categories))
If you have access to the Recital Workbench, you can use the modify structure worksurface to add and alter your dictionary entries, including a customized error message if required.
Recital is a dynamic programming language with an integrated high performance database particularly well suited for the development and deployment of high transaction throughput applications. Recital 10 further enhances Recital with extensive features and functionality to facilitate its use in fault tolerant high availability systems. Much of the development of Recital 10 was concentrated on performance optimizations and cluster aware functionality to provide an application platform that can be scaled as needed without any application changes.
Key features of Recital 10 include:
- Cluster aware database engine that works transparently with drbd, heartbeat, glusterfs and samba
- High degree of fault tolerance with self healing indexes
- Massive performance improvements
- Extensive internals overall and modernization with superior object-oriented capabilities
- Chronological data versioning with database timelines
- SmartQuery caching
- Database Administration Tools
- Code and Data Profiling
- Better integration with unix/linux command shell
- Incorporates a range of new built-in functions compatible with those in the PHP core libraries
- Built-in support for outputting data in HTML, XML, and JSON format
- Seamless SQL command integration into the Recital scripting language
- Much improved Microsoft FoxPRO language compatibility
- Numerous extensions and improvements (see below for details)
- Very large file support (2^63)
The Openfiler NAS/SAN Appliance (NSA) is a Storage Management Operating System / NAS Appliance distribution. It is powered by the Linux 2.6 kernel and Open Source applications such as Apache, Samba, LVM2, ext3, Linux NFS and iSCSI Enterprise Target. Openfiler combines these ubiquitous technologies into a small, easy to manage solution fronted by a powerful web-based management interface. Openfiler allows you to build a Network Attached Storage (NAS) and/or Storage Area Network (SAN) appliance, using industry-standard hardware, in less than 10 minutes of installation time.
Building upon the popularity of server virtualization technologies such as VMware, Virtual Iron, and Xen, Openfiler can also be deployed as a virtual machine instance or on a bare metal machine.
This deployment flexibility of Openfiler ensures that storage administrators are able to make the best use of system performance and storage capacity resources when allocating and managing networked storage in a multi-platform environment.
Openfiler is ideally suited for use with High Availability Recital applications as it incorporates:
- Heartbeat cluster manager
- drbd disk replication
- CIFS
- NFS
- Software and hardware RAID
- FTP
- rsync
- HTTP/DAV
- iSCSI
- LVM2
- Multiple NIC bonding for High Availability
- Powerful web-based GUI
- For building shared libraries on the MAC the following need to be set
-
- The shared library file extension should be .dylib
- The compile flag is -dynamic
- For accessing the shared libraries at runtime
-
- DYLD_LIBRARY_PATH needs to be set to the location of the shared libraries
- Useful utilities for shared library support
-
- The following command will display the table of contents of the dynamically linked library
otool -TV sharedlibraryfile.dylib