It seems that the much simpler solution would just be to lower the min- ttl to 20. If I setup the open source scalr so that I can do this -- is there anything different about the open source vs. the paid version? Does the open source version code base have all the updates that the paid version has?
Thanks, Cole On Apr 9, 5:51 pm, Alex Kovalyov <[email protected]> wrote: > Check DB role availability prior to attempting to query database. > > Options: > 1. [Suitable for object-oriented code.] > Assign a script to OhostUp event for DB role. Script will set a file > (or whatever)-based mutex. > > 2. [Suitable for scripting.] > Do mysql_ping() (function name will likely be spelled differently in > other DBMS' APIs ) in bootstrapping code and set a mutex. > > Do query only if the mutex is set, otherwise display sorry message . > above two can be combined for better durability:) > > We have a to-do item saying "Ability to set the order in which roles > are launched". Should be ready in this or next release. > Still, the above things are essential. > > On 8 апр, 08:03, Cole <[email protected]> wrote: > > > Ok - that makes sense, but if trying to reach the master before it's > > up is causing the delay - how can we fix that? This would almost > > always happen whenever there is activity to the database and a failure > > occurred. > > > On Apr 7, 5:56 am, Nickolas Toursky <[email protected]> wrote: > > > > Hi Cole, > > > > When you first requested int-mysql-master IP address, it probably > > > failed to resolve and a negative response (NXDOMAIN) was cached for > > > 300 seconds. This could happen if you are requesting int-mysql-master > > > IP before it was fully initialized. > > > > Nick > > > > On Apr 7, 7:17 am, Cole <[email protected]> wrote: > > > > > If this is true, then what could be causing the delay? > > > > > Thanks, > > > > Cole > > > > > On Apr 6, 4:15 pm, Nickolas Toursky <[email protected]> wrote: > > > > > > Hi Cole, > > > > > > This value is intented to be used as the minimum possible TTL for the > > > > > zone as per RFC 1035, but in fact it only reflects negative caching > > > > > time to live. In other words, for this number of seconds NXDOMAIN > > > > > reponse (DNS entry not found) is returned by resolver after it has > > > > > failed to resolve domain name. > > > > > > Regards, > > > > > Nick > > > > > > On Mon, Apr 6, 2009 at 9:07 PM, Cole <[email protected]> wrote: > > > > > > > If you are logged into Scalr and on the Home tab, just click > > > > > > applications, then in your application (must be running), under > > > > > > options select "Edit DNS Zone". Once you have the DNS options up, > > > > > > you > > > > > > will see right at the top Minimum TTL listed as 300 -- and you can > > > > > > not > > > > > > change this value. Any ideas? > > > > > > > Thanks, > > > > > > Cole > > > > > > > On Apr 2, 8:08 pm, Alex Kovalyov <[email protected]> wrote: > > > > > >> On Thu, Apr 2, 2009 at 8:36 PM, Cole <[email protected]> > > > > > >> wrote: > > > > > > >> > In Scalr's DNS I have noticed the is has a setting for Minimum > > > > > >> > TTL > > > > > >> > which cannot be changed, and is set at 300. > > > > > > >> May I ask you to point me to the place where you're seeing this > > > > > >> value? > > > > > > >> > overriding the 20 ttl for the int-myswl-master. Is there anyway > > > > > >> > to > > > > > >> > change this so that the DNS updates quickly in case of a failure? > > > > > > >> > On Apr 2, 2:04 am, Cole <[email protected]> wrote: > > > > > >> >> Hi, > > > > > > >> >> Thank you so much for your response, it was very helpful. > > > > > > >> >> I have a few morequestionsas well. > > > > > >> >> I have setup a mysql farm on scalr with 3 instances, but I am > > > > > >> >> having > > > > > >> >> trouble accessing the master through a Windows instance that is > > > > > >> >> also > > > > > >> >> on the same AWS account. This windows instance is hosting the > > > > > >> >> domain > > > > > >> >> name I own. > > > > > > >> >> The issue is that after I shut down the master mySql server (to > > > > > >> >> simulate a crash) and let a slave automatically promote itself > > > > > >> >> to a > > > > > >> >> master, it takes a long time for the DNS (5 minutes at least) > > > > > >> >> to be > > > > > >> >> correctly resolved on this windows instance. > > > > > > >> >> If from a cmd prompt I do: > > > > > >> >> nslookup int-mysql-master.db2test.mydomain.com > > > > > > >> >> I will get the follow response: > > > > > >> >> Server: ip-172-16-0-23.ec2.internal > > > > > >> >> Address: 172.16.0.23 > > > > > >> >> *** ip-172-16-0-23.ec2.internal can't find int-mysql- > > > > > >> >> master.db2test.forexonthego.com: Non-existent domain > > > > > > >> >> The odd thing though, is if I keep doing the nslookup, after a > > > > > >> >> while > > > > > >> >> it will finally show me the correct address, at which point I > > > > > >> >> can then > > > > > >> >> login to mysql through the int-mysql-master. If I just use the > > > > > >> >> correct internal IP that scalr shows in the dns panel, I can > > > > > >> >> log in > > > > > >> >> that way (long before the dns starts resolving correctly). > > > > > > >> >> Incase this helps, in Scalr the dns settings for the things I > > > > > >> >> can > > > > > >> >> change are: > > > > > >> >> www 14400 IN CNAME db2test.mydomain.com. > > > > > >> >> db2test.mydomain.com. 14400 IN NS ns3.scalr.net. > > > > > > >> >> At godaddy (my domain registra) I added to the name servers to > > > > > >> >> have > > > > > >> >> db2test pointing to ns1.scalr.net, ns2.scalr.net, and > > > > > >> >> ns3.scalr.net > > > > > >> >> Any ideas for this? > > > > > > >> >> Thanks, > > > > > >> >> Cole > > > > > > >> >> On Apr 1, 10:03 am, Nickolas Toursky <[email protected]> wrote: > > > > > > >> >> > Hi Cole, > > > > > > >> >> > 1. MySQL data snapshotting routine locks databases for write > > > > > >> >> > queries > > > > > >> >> > for some time, but they are still available for reads. Lock > > > > > >> >> > time > > > > > >> >> > heavily depends on data storage engine chosen. For large > > > > > >> >> > databases you > > > > > >> >> > should consider using either LVM or EBS storage. Anyway, > > > > > >> >> > exact lock > > > > > >> >> > time could only be determined experimentally for your setup. > > > > > > >> >> > 2. Databases backup feature uses 'mysqldump' utility with all > > > > > >> >> > of its > > > > > >> >> > dis/advantages. Backups are stored on S3. Again, backup time > > > > > >> >> > depends > > > > > >> >> > on many factors and could not be predicted in general. > > > > > > >> >> > 3. If EBS was chosen as data storage engine, all the EBS > > > > > >> >> > management > > > > > >> >> > will be done automatically. You don't have to setup > > > > > >> >> > volumes/snapshots > > > > > >> >> > on the EBS tab. > > > > > > >> >> > 4. All the availability zones in the US are placed on the > > > > > >> >> > east coast. > > > > > >> >> > If you need your instances to be in the different > > > > > >> >> > availability zones, > > > > > >> >> > you should choose 'Place in different zones' option for > > > > > >> >> > 'Placement' in > > > > > >> >> > the role settings ("Placement and type" tab). > > > > > > >> >> > 5. int-mysql subdomain round-robins through all the MySQL > > > > > >> >> > instances, > > > > > >> >> > this is correct. You should use int-mysql-master for write > > > > > >> >> > queries. > > > > > > >> >> > Nick > > > > > > >> >> > On Wed, Apr 1, 2009 at 8:01 AM, Cole <[email protected]> > > > > > >> >> > wrote: > > > > > > >> >> > > Hello, > > > > > > >> >> > > I've just setup Scalr so that I can get some highly > > > > > >> >> > > available MySQL > > > > > >> >> > > servers up on EC2. I am new, and looking for any > > > > > >> >> > > documentation or > > > > > >> >> > > info about Scalr, and I can't hardly find anything, so if > > > > > >> >> > > you know of > > > > > >> >> > > any, please point me in the right direction. > > > > > > >> >> > > In the mean time, I have a fewquestionsthat would really > > > > > >> >> > > help me out > > > > > >> >> > > if you could answer. > > > > > > >> >> > > 1. When setting up a mysqllvm farm, if I enable "Bundle and > > > > > >> >> > > save mysql > > > > > >> >> > > data snapshot every 48hrs" Will the database be > > > > > >> >> > > unavailable while the > > > > > >> >> > > bundle is taking place? If so, how long will it be > > > > > >> >> > > unavailable? > > > > > > >> >> > > 2. If I enable "Periodically backup databases every 15 > > > > > >> >> > > mins" will the > > > > > >> >> > > backup cause any interruption to the database service? If > > > > > >> >> > > so how > > > > > >> >> > > long, and what type of backup is being performed (an > > > > > >> >> > > export?) and > > > > > >> >> > > where is it stored? > > > > > > >> >> > > 3. If under storage engine in the MySQL Settings tab I > > > > > >> >> > > select EBS, do > > > > > >> >> > > I need to also specify to attach an empty EBS volume under > > > > > >> >> > > the EBS > > > > > >> >> > > tab? Or will doing that create a second EBS drive? > > > > > > >> >> > > 4. When I build a farm I have to select an east or west > > > > > >> >> > > coast region. > > > > > >> >> > > How can I put a slave in a different zone for redundancy? > > > > > > >> >> > > 5. In the information I could find, Scalr uses a single > > > > > >> >> > > master multi > > > > > >> >> > > slave system for MySQL -- but DNS round robins, so that > > > > > >> >> > > write could go > > > > > >> >> > > to any of the instances, not just the master. This seems > > > > > >> >> > > more like a > > > > > >> >> > > master-master setup. Which one is it? And is there some > > > > > >> >> > > type of > > > > > >> >> > > locking mechanism that prevents errors, such as a primary > > > > > >> >> > > key being > > > > > >> >> > > issued to two different instances at the same time? > > > > > > >> >> > > Thanks in advance for you help, > > > > > >> >> > > Cole --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "scalr-discuss" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/scalr-discuss?hl=en -~----------~----~----~----~------~----~------~--~---
