[CentOS] iSCSI best practices

[John R Pierce]

On 12/12/11 6:43 AM, Digimer wrote:
> I handle this by setting up two servers running DRBD in active/active
> with a simple two-node red hat cluster managing a floating IP address.
> The storage network link uses a simple Active/Passive (mode=1) bond with
> either link go to separate switches.

DRBD with synchronous writes?  doesn't that slow things down 
considerably?   if its asychronous, recently written data will be lost 
on a failure.

proper storage appliances implement a shared cache between the master 
and standby storage controllers so that if the master fails, the standby 
has all data, including cached writes.   as far as I know, there's no 
way to easily implement this with open source, its part of the secret 
sauce of proper redundant storage.

without this, its not safe to run a transactional database server on 
your storage

-- 
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast