Réf. : Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread bsimon

Thanks a lot Scott.

It seems that we were totally wrong when considering a network storage solution. I've read your techdoc http://techdocs.postgresql.org/guides/DiskTuningGuide and found many interesting remarks. 
I think that we will know focus on external Raid systems which seem to be relativily affordable compared to NAS or SAN (we would have had the budget for one of these). 
As we don't plan to have more than 5 connections (I.E process), we think SATA drives would fit our requirements. Could this be an issue for an after crash recovery ?
We also hesitate concerning the raid level to use. We are currently comparing raid 1+0 and raid 5 but we have no actual idea on which one to use.

Our priorities are : 
1) performance
2) recovery
3) price
4) back-up 

It could be nice to have any comments from people who have already set up a similar platform, giving some precise details of the hardware configuration :
- brand of the raid device, 
- technology used (SCSI/IDE, RAID level ...), 
- size of the database, number of disks/size of disks ...

Such a knowledge base may be useful to convince people to migrate to opensource cheap reliable solutions. 
Thanks again.

Benjamin.








Scott Marlowe [EMAIL PROTECTED]
Envoyé par : [EMAIL PROTECTED]
20/07/2004 10:20


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Objet :Re: [PERFORM] NAS, SAN or any alternate solution ?


On Tue, 2004-07-20 at 01:52, [EMAIL PROTECTED] wrote:
 Hi all,
 
 I've been searching the list for a while but couldn't find any
 up-to-date information relating to my problem.
 We have a production server with postgresql on cygwin that currently
 deels with about 200 Gigs of data (1 big IDE drive). We plan to move
 to linux for some reasons I don't have to explain.
 Our aim is also to be able to increase our storage capacity up to
 approximately 1 or 2 terabytes and to speed up our production process.
 As we are a small microsoft addicted company , we have some
 difficulties to choose the best configuration that would best meet our
 needs.
 Our production process is based on transaction (mostly huge inserts)
 and disk access is the main bottlle-neck.
 
 Our main concern is hardware related :
 
 Would NAS or SAN be good solutions ? (I've read that NAS uses NFS
 which could slow down the transfer rate ??)
 Has anyone ever tried one of these with postgresql ? 

Your best bet would likely be a large external RAID system with lots o
cache. Next would be a fast internal RAID card like the LSI Megaraid
cards, with lots of drives and batter backed cache. Next would be a
SAN, but be careful, there may be issues with some cards and their
drivers under linux, research them well before deciding. NFS is right
out if you want good performance AND reliability.

The cheapest solution that is likely to meet your needs would be the
internal RAID card with battery backed cache. 


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Réf. : Re: Réf. : Re: [PERFORM] NAS, SAN or any alternate solution ?

2004-07-20 Thread bsimon

I must say that cygwin did well (there exists good software on windows, i've found one)... as a prototype ... when I look at the postgresql poll (http://www.postgresql.org/survey.php?View=1SurveyID=11), it seems like I'm not alone !!
Actually, the major problem was the limit of the available allocable memory restricted by cygwin.

We don't plan to wait for the 7.5 win native version of postgresql. It was hard enough to decide moving to linux, I don't want to rollback everything :)
Thanks for the advice, I will definetely have a look at the new version anyway as soon as it is released.

Regards,
Benjamin.







Mark Kirkwood [EMAIL PROTECTED]
20/07/2004 12:04


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Objet :Re: Réf. : Re: [PERFORM] NAS, SAN or any alternate solution ?




[EMAIL PROTECTED] wrote:


 As we don't plan to have more than 5 connections (I.E process), we 
 think SATA drives would fit our requirements. Could this be an issue 
 for an after crash recovery ?

If you can disable the write ATA write cache, then you have safety. 
Unfortunately many cards under Linux show up as SCSI devices, and you 
can't access this setting. Does anyone know if the newer SATA cards let 
you control this?

You might want to keep and eye on the upcoming native windows port in 
7.5 - It will come with a fearsome array of caveats... but you have been 
running cygwin in production! - and I am inclined to think the native 
port will be more solid than this configuration.

regards

Mark