There has been some comments in my old posts trying to use generated country lists in Apache .htaccess. This approach is wrong, and I will show you much better way how to block or allow specific country.
Using mod_geoip in .htaccess
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Author Archives: iwik
Generating country IP ranges lists #2
My original article about this topic is more that year old and was using Regional Internet Registries (RIRs) list as source and was in python. This post will describe other simple solution how to generate some country IP ranges list.
Performance impact when using VMware snapshots
Using vmware and snapshots? You probably know about vmware best practices about snapshots, which includes
- The maximum supported amount of snapshots in a chain is 32. However, VMware recommends that you use only 2-3 snapshots in a chain.
- Use no single snapshot for more than 24-72 hours. Snapshots should not be maintained over long periods of time for application or Virtual Machine version control purposes.
- An excessive number of delta files in a chain (caused by an excessive number of snapshots) or large delta files may cause decreased virtual machine and host performance.
- Be especially diligent with snapshot use on high-transaction virtual machines such as email and database servers
But what is real performance inpact of snapshot?
Dropbox on network drive
Have you tried to place your Dropbox folder on network (NAS) drive? Dropbox don’t allow it directly, but there is hack…
Continue reading
8GB FC or 10GB iSCSI?
I have just found very interesting post on reddit about 8GB FC vs 10GB iSCSI. Continue reading
Protecting WordPress with mod-security
This my blog and also other hosted websites running WordPress are target of bots trying passwords to wordpress admin and posting spam comments. I was unable to found simple plugin for comments dns blacklist, so I focused to mod-security. Continue reading
Replacing vCenter Server Appliance SSL certificates
vCenter and SSL is always a pain. Simple thing as replacing default self-signed SSL certificates with CA signed has in official VMWare KB2057223 40(!!!) steps. Continue reading
Big XFS filesystem NFS export mount fails with stale nfs handle
If you have big XFS filesystem (with lot of files) and you use inode64 mount option, exporting this file system using NFS may fail when mouting this export on client:
Stale NFS file handle
This error is strange and confusing. Workaround is to specify fsid in /etc/exports for this filesystem.
For more information check this nice blog article https://hpc.uni.lu/blog/2014/xfs-and-inode64/
Snapshoting virtual machine running mysql database
Backup in virtualized enviroment is mostly based on snapshoting entire virtual machine and saving this state to backup repository. This snapshot does not include memory of virtual machine. When you restore virtual machine from this snapshot filesystem is in unclean state, but journal filesystem can handle this. From mysql point of view server crash happended and database can be corrupted and unrecoverable, depending on what queries where running during snapshot. This unpredicted and unconsistent state you don’t want to have as a backup of your data. Continue reading
VMware backup script
I have been searching for simple and easy script to backup selected virtual machines running on esxi server, which will:
- run on linux – do not require windows machine; can’t use PowerCLI
- do not require direct access to esxi host using ssh (as other backups scripts like ghettoVCB.sh do) and will use API
- support multiple esxi hosts managed by vcenter
- have clear code – that means no perl hell (including big vsphere perl sdk)
- have short code
- can be put into cron
I was unable to find any to comply my requirements. I’m learning python, so I searched for some python vsphere libs and found psphere. Then backup.py has born.