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#1
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Sharing RAID0 between LAMP servers?
Hello
Our LAMP application is showing I/O latency. I was wondering if we could move to multiple Apache servers, each connected through their own disk controller to a single, shared RAID0 bay? Our hoster recommends that we use a NAS, but I'm concerned about network + NFS latency. Thank you for any tip. |
#2
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Sharing RAID0 between LAMP servers?
Gilles Ganault wrote:
Hello Our LAMP application is showing I/O latency. I was wondering if we could move to multiple Apache servers, each connected through their own disk controller to a single, shared RAID0 bay? Our hoster recommends that we use a NAS, but I'm concerned about network + NFS latency. Thank you for any tip. Where's the latency being seen? Between the user and the application or from the application to the storage? If you have latency from the application (mysql/apache) to the storage then higher performance storage is needed - more disks and/or more cache - regardless of the number of servers. If you need several servers accessing the same dataset and it's largely reads, NFS is the easiest way. If you want to directly connect several servers to the same storage you'll need a storage controller which allows multiple devices to access the storage and you'll need to install a cluster filesystem. That's a load of complexity that you could probably do without. If you have a dedicated network, then the latency of NFS & the network is going to be insignificant compared to the latency of a disk access. Pete |
#3
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Sharing RAID0 between LAMP servers?
Gilles Ganault wrote:
Hello Our LAMP application is showing I/O latency. I was wondering if we could move to multiple Apache servers, each connected through their own disk controller to a single, shared RAID0 bay? Our hoster recommends that we use a NAS, but I'm concerned about network + NFS latency. Thank you for any tip. You sound confused about all this. What is the problem you're experiencing, or how did you arrive at "showing I/O latency" as the bottlneck in this case? |
#4
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Sharing RAID0 between LAMP servers?
On Mon, 25 Aug 2008 12:15:01 GMT, Pete
wrote: Where's the latency being seen? Between the user and the application or from the application to the storage? Thanks guys for the input. It was between the www servers and the MySQL + JPGs server. We asked the hoster to add a filer, and performance is much better now, with the filter being shared between two Apache servers If demande keeps rising, I guess we'll have to investigate MySQL clusters, so that the DB doesn't become the bottleneck again. If you want to directly connect several servers to the same storage you'll need a storage controller which allows multiple devices to access the storage and you'll need to install a cluster filesystem. That's a load of complexity that you could probably do without. Yes, that's what I suspected :-/ So I guess the standard solution to scaling databases is to add some kind of load balancer, and 2 or more DB servers behind it. |
#5
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Sharing RAID0 between LAMP servers?
Gilles Ganault wrote:
On Mon, 25 Aug 2008 12:15:01 GMT, Pete wrote: Where's the latency being seen? Between the user and the application or from the application to the storage? Thanks guys for the input. It was between the www servers and the MySQL + JPGs server. We asked the hoster to add a filer, and performance is much better now, with the filter being shared between two Apache servers If demande keeps rising, I guess we'll have to investigate MySQL clusters, so that the DB doesn't become the bottleneck again. If you want to directly connect several servers to the same storage you'll need a storage controller which allows multiple devices to access the storage and you'll need to install a cluster filesystem. That's a load of complexity that you could probably do without. Yes, that's what I suspected :-/ So I guess the standard solution to scaling databases is to add some kind of load balancer, and 2 or more DB servers behind it. It's really to tune things first, then as a last resort, start adding more hardware. More hardware and more layers is always harder to manage. As junior as mysql is, there's lots of stuff that can be tweaked. The apps using it should be examined as well if you are running into performance problems. |
#6
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Sharing RAID0 between LAMP servers?
On Wed, 27 Aug 2008 20:45:11 +0000 (UTC), Cydrome Leader
wrote: It's really to tune things first, then as a last resort, start adding more hardware. More hardware and more layers is always harder to manage. I'll make sure MySQL + queries are configured as best as possible. Thanks. |
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