server experts - how would you set this up

[longdongsilver]

We have 2 servers, same spec. Each server has 2 ssd drives. These servers can be linked through a virtual rack.

I was told it would be best to do this but not sure it looks correct.

Server 1

main website - drive1
mysql data base replicated (from drive 2 on server 2) - drive 2


Server 2

mysql data base master - drive 1

mysql replicated - drive 2


we have a small nas too for backing up the main site and data base daily.


The mysql is growing rather large.

Is this a strange way of doing things?



what is the difference between say mysql replicated, or master and slave say and having the 2 drives in server2 just put in a raid 1 config??

I have no idea really about this kind of thing.



Sorry just to make it clear what i meant in the last part...

on server 2 - why not just put the database on a raid 1 to replicate it. Why has he put DB replicated (slave) for drive 2.

Is not backing up a db the same as replicating it?



I would have thought just do it like this

Server 1 -

main site - drive 1
main site - drive 2

in raid 1


server 2
mysql - drive1
mysql- drive 2

in raid 1

nas storage

mysql backed up and website backed up.

[AdultEUhost]

honestly, if you don't really know what you are doing you shouldn't try, especially with valuable data like databases but simply ask your host. You shouldn't be doing their work in the first place, let them set it up.

Not sure what you mean with virtual rack. If the servers have 4 solid state drives with consecutive serials you have another problem by the way, assuming the SSDs don't break down in between they will likely all wear out around the same time What SSDs are you using?

[longdongsilver]

Originally Posted by AdultEUhost

honestly, if you don't really know what you are doing you shouldn't try, especially with valuable data like databases but simply ask your host. You shouldn't be doing their work in the first place, let them set it up.

Not sure what you mean with virtual rack. If the servers have 4 solid state drives with consecutive serials you have another problem by the way, assuming the SSDs don't break down in between they will likely all wear out around the same time What SSDs are you using?

thanks for your reply,

I think they are intel 320 series ssd

I am not sure if they have consecutive serial numbers, yes that is worrying i will try to find out if they have.

Our host does not do full management, we hired a server admin on a recommendation from a friend.

However i was just trying to see if what he is suggesting makes any sense. Im sure it does and that its just it makes no sense to me as i know nothing about servers really at all.

He seems to think that this set up could allow us to do the backups to nas without stopping the master db. I think that is what he was saying.

The virtual rack just means the servers are networked together.

From what i am starting to understand, simply copying a db (backing it up) is not the same as replication. Seems its not like just a giant file.

[AdultEUhost]

Originally Posted by longdongsilver

He seems to think that this set up could allow us to do the backups to nas without stopping the master db. I think that is what he was saying.

Well you can always run a mysqldump and then scp it over to a different host or do the mysqldump on the remotehost directly (depending if you have networking enabled for mysql).

If you can't have locked tables etc you should setup replication where server 1 is the master and server 2 is the slave, this is done through binary logs so each write query is performed on both servers. You can perform reads on either one of the servers. In this case you also opt to make the backups on the slave so your master is always able to perform queries.

Originally Posted by longdongsilver

From what i am starting to understand, simply copying a db (backing it up) is not the same as replication. Seems its not like just a giant file.

A mysqldump is an export file with all the queries in it to recreate a database, tables and data. Replication is where all queries on a master are replicated to a slave so both hosts contain the same data (if in sync of course).

[oscer]

Unless your Trying to keep a "HOT SPARE" I would have just put the drives in raid 1 and done a good MYSQL backup often , Use one server for SQL if you are very SQL intensive and one server for Web and Data ... Just my thoughts

[raymor]

Everything you've mentioned sounds questionable.

I don't see why he'd want to replicate the database on the same server. He may have a good reason, but that's not normal and you didn't post a reason. Since it's already replicated to server #2, and hot backup tools exist, backing up from the third replucate isn't a good answer, not when you're talking about DOUBLING the writes. My GUESS is that he may be trying to spread the load across both drives way. If so, that's one of the most naive methods I've seen.

Is there any reason to say the database on this drive, the site on this other? You'd get better performance and far better flexibility with either RAID or LVM, so either process can use both drives as needed. When the DB is busy, it has both drives, when site has several large downloads, it can use both. When the site grows, it can use space on both, or adding another to the pool is simple.

As you said, replication is NOT backup. With a backup, when he makes a mistake and messed up the database by forgetting the WHERE clause, he can restore it from that morning's backup. If a hacker wipes it out, just restore. Replication, like RAID, is real time - you just have two copies of garbage.

Your backup is protects you when there is a fire, an FBI raid, etc. You can use the backup to get running with another host. That's one reason the NAS provided by your host isn't a proper backup. If they go like Alphared, Acronoc, etc., or have a fire like The Planet, you're out of business. Thousands of servers were taken out by the fire at The Planet. What good does that NAS do you when it melts in the same fire that melts your server? Proper backups, backups for your business, must be:
Automatic (or they won't be done regularly)
Tested (recently one host pointed us to the "backups" - they had stopped working 20 months prior.)
Offsite (fire, FBI, host doesn't pay $50,000 bandwidth bill, etc.)
Rotated (a midnight backup is worthless is you got hacked at 11:45)
QUICKLY restorable (tape backups can take days to get a single file)

Those are the key attributes of proper backups, the kind that keep you from going out of business when shit happens, and shit WILL eventually happen. They are the essential characteristics to measure a backup proposal by and compare to an enterprise grade system such as Clonebox.

[AdultEUhost]

Originally Posted by oscer

Unless your Trying to keep a "HOT SPARE" I would have just put the drives in raid 1 and done a good MYSQL backup often , Use one server for SQL if you are very SQL intensive and one server for Web and Data ... Just my thoughts

I wouldn't do RAID1 with SSD drives, chances that your raid controller die are more likely before the SSD drive. Besides your drives are gonna wear out at pretty much the exact same moment.

[raymor]

Originally Posted by AdultEUhost

honestly, if you don't really know what you are doing you shouldn't try, especially with valuable data like databases but simply ask your host. You shouldn't be doing their work in the first place, let them set it up.

Trust the professionals yes, trust but verify. Don't hire a "pro" and pay them to do a bunch of stupid, creating problems for you. I think the OP is spot on to get a proposal from the admin, then run it by people like you and I to check it for reasonableness.

[darksoul]

raid on SSD is pointless. Ditch the replica from drive 2 server 2 as well as it doesn't make a lot of sense.
I would put a copy of the website on the second server as well so you have two identical servers just in case one of them goes bust.

[Barefootsies]

Cue all 'masters of the universe'... my way is better than your way, you're an idiot, etc..

[longdongsilver]

thanks guys, for all of your input on this. I am going to ask the tech to just read this thread and see if he can explain more of why he is doing it the way he suggested.