Browsing articles tagged with "highavailability - 5/16 - Admins Goodies"
Aug 24, 2011
tom

Data loss due to MySQL DRBD Heartbeat failover script

Using DRBD version: 8.2.6 (api:88/proto:86-88) Here is the contents of /etc/ha.d/haresources db1 192.168.100.200/24/eth0 drbddisk::mysql Filesystem::/dev/drbd0::/drbd::ext3::defaults mysql and /etc/ha.d/ha.cf logfile /var/log/ha-log logfacility local0 keepalive 1 deadtime 30 warntime 10 initdead 120 udpport 694 bcast eth0, eth4 auto_failback off node db1 node db2 respawn hacluster /usr/lib64/heartbeat/ipfail apiauth ipfail gid=haclient uid=hacluster deadping 5 When testing failover between machines I ran the following commands on db2: service heartbeat stop service mysqld stop drbdadm down mysql service drbd stop /proc/drbd […]

Continue Reading »
Aug 24, 2011
tom

NFS v4, HA Migration, and stale handles on clients

I’m managing a server running NFS v4 with Pacemaker/OpenAIS. NFS is configured to use TCP. When I migrate the NFS server to another node in the Pacemaker cluster, even though the metadata is persisted, connections from the clients ‘hang’ and eventually time out after 90 seconds. After that 90 seconds, the old mountpoint becomes ‘stale’ and the mounted files can no longer be accessed. The 90 second grace period seems to be part of the […]

Continue Reading »
Aug 24, 2011
tom

High availability LDAPS with Fedora Directory Server

I’ve been asked to set up a HA LDAP architecture using Fedora Directory Server – the company currebnly uses Sun DS but wants to move away from Sun. I want to use a network hardware loadbalancer (Cisco) so that clients can just use ‘ldap.business.com’ as the LDAP server name, with the real IPs of the 4 servers behind it hidden. For plain LDAP this works well, but now I want to add LDAPS using TLS. […]

Continue Reading »
Aug 23, 2011
tom

ReadyNAS 2100 iSCSI and ESX Server 3 – Multiple Host Connections

I have a simple VMWare ESX Server 3 farm (plus Virtual Infrastructure/HA) that is running off of a single iSCSI SAN. We have a NetGear ReadyNAS 2100 set up as an iSCSI target with two volumes (mirroring the iSCSI SAN). Its job is to run as a backup should the primary fail and also as primary storage for some really large, non critical VMs. I have successfully added it to my storage cluster except that […]

Continue Reading »
Aug 23, 2011
tom

Windows Server 2003 Availability / Uptime

I’m looking at putting together a support SLA. As a base line I’d like to know roughly what sort of percentage availability I should expect from a non-clustered Windows 2003 Server. Assumptions are that the server is comfortably spec-ed for the application it’s running (so it won’t be labouring) and that by uptime I mean that the server is available. It needs to undergo reasonalbe general maintenance (security patching and the like). What would people […]

Continue Reading »
Aug 23, 2011
tom

LVS Cluster Help

I’m trying to set up an LVS Cluster for a project and I don’t have a lot of knowledge in these layers of networking. I’ve run into an issue where the real server rejects any packets from the director, but will allow packets to the same port from my client. I’m using suse linux on a 2.6.16.60-0.21-default kernel. director script: #!/bin/bash #———-mini-rc.lvs_dr-director———————— #set ip_forward OFF for lvs-dr director (1 on, 0 off) #(there is no […]

Continue Reading »
Aug 22, 2011
tom

Xen Live Migration with Gluster

Has anyone used or found a HOWTO on how to use Xen with Gluster? I’m working on a testbed of two servers, possibly three, that will be syncing a volume via IP and I’d like to work on finding a way to do live migration of the VM between (among) the servers but I don’t see any howtos for setting that up or managing it. I know a couple people who run DRDB. What that […]

Continue Reading »
Aug 22, 2011
tom

How to perform cron jobs failover?

Using two Debian servers, I need to setup a strong failover environment for cron jobs that can be only called on one server at a time. Moving a file in /etc/cron.d should do the trick, but is there a simple HA solution to operate such action ? And if possible not with heartbeat I think heartbeat / pacemaker would be the best solution, since they can take care a lot of a lot of race […]

Continue Reading »
Aug 22, 2011
tom

Fault tolerance on nameservers

I have 3 servers each running a nameserver and a webserver. Today, 2 of the servers went down. I thought the last server would handle all future requests from then on out, but that only seemed to happen a fraction of the time. Other times, requests would time out. On each of my servers, I have zone entries with the following: ns1 IN A <SERVER IP 1> ns2 IN A <SERVER IP 2> ns3 IN […]

Continue Reading »
Aug 22, 2011
tom

Software for failover across multiple external hosts

I have multiple webservers with the same content, hosted across different providers. However, I can’t seem to find a nice, simple failover solution. Load-balancing software (Pound, HAProxy, etc.) are unnecessary, and I need the flexibility to manage over 100+ domains, so the paid DNS failover solutions I’ve found are too expensive. So far the simplest solution I’ve thought of is just to set a very low TTL (30min – 1hr) in each zone entry on […]

Continue Reading »
Pages:«12345678...16»