RAID 5 ? Fast ? Oh come on ! The performance of any RAID array is very low comparing to a BUSY mail server if data integrity is an important aspect.
I'd recommend only the Raid 10 which does a strip over two mirrors. Meaning you have 4 drives, they each are in a RAID 1 array and the two RAID 1 arrays are part of a RAID 0 array. That is some performance oriented array. The simple RAID 5 is slow when it comes to writing many small files. If you can afford it you may think of the RAID 50 array that basically requires a minimum of 6 harddrives. For a busy server you could try to put the queue in a ramdisk if you have say a 4G of RAM machine or even more. LVM is the recommended way if you need to increase the filesystem available space without blowing away your installation. EXT 3 supports on-line filesystem growing and shrinking so you will only need to stop the machine to put in the physical drive in it. I only worked with some intel based hw controllers but maybe there are controllers that support adding harddrives without stopping the machine. It is recommended to use a controller with a battery backup if you intend to use write caching (which will boost performance by the way). You should also look into tune2fs for fine tuning the filesystem, check for inode size information. Mounting the partition were you store the queue with the noatime flag is also helpful. Hope this was helpful. And please remember what this mailist is about ;) > > Rob - thanks. Anyone care to comment on the 3ware SATA RAID cards? > > > At 03:29 PM 9/6/2007, you wrote: >>Over time I've used a few different scenarios and found all of them to >> work >>just fine. We've used the Dell CERC RAID controllers (Adaptec), and the >>regular branded Adaptec RAID controllers. I normally create a giant RAID >> 5 >>array out of all of my disks then just create a /boot, /, and swap >>partition. I do make sure I have the swap partition set to at least 2048M >>because files that are in and out of the tmp directory or queue >> directories >>seem to work better if you have a bigger swap. >> >>If you're wondering why I didn't manually create each individual >> partition, >>it's because of future space requirements. I might sacrifice a tiny bit >> of >>performance by breaking up the root directories into partitions, but I >> would >>rather do that than run out of disk space on one partition and have to >> blow >>away my installation completely just to resize one partition. >> >>If you're just looking for the reliability of RAID and not necessarily >> the >>performance increase of it, I'd make sure you stick to a hardware RAID 1 >>setup. If you have a little extra cash and room in your server, it's >> always >>better to have a RAID 5 over a RAID 1 and get some SATAII drives. I've >> ran >>into several circumstances where a RAID 1 array has failed and I still >> get >>corrupt data. I've never ran into that with a RAID 5 setup. For >> performance >>and reliability, I'd go either with the Adaptec 2251800-R or the Adaptec >>2220300-R cards. The storage manager is extremely easy to work with and >> it >>even does alerting if you have it setup correctly. >> >>Ryan >> >>-----Original Message----- >>From: Jeff Koch [mailto:[EMAIL PROTECTED] >>Sent: Thursday, September 06, 2007 2:32 PM >>To: toaster@shupp.org >>Subject: RE: [toaster] toaster RAID setup >> >> >>Hi Ryan: >> >>How do you have the file systems setup on the SATA RAID machine. Do you >>have the entire toaster on the RAID 5 array? (i.e. the qmail queue as >> well >>as the /home/vpopmail/domain directories). Which SATA RAID card are you >>using and do you have write caching enabled. >> >>In our case we're not really looking for a speed increase - mainly just >>reliability - so we though RAID 1 mirroring would help. >> >> >>At 01:26 PM 9/6/2007, you wrote: >> >I've run a SATA setup in one location for about 3 years now and a SAS >> setup >> >for about a year now. We've run RAID 5 on both setups and the servers >> have >> >over 1000 domains each. I've never seen any performance hits on the >> systems >> >at all. It seems like the only thing that helps performance of either >> of >>the >> >systems were the type of CPU's I had. The newer machine with 2 x dual >> core >> >XEON CPU's seems to process anything you throw at it with no issues at >> all. >> >The entire toaster install only took 15 minutes on that machine. >> > >> >Ryan >> > >> >-----Original Message----- >> >From: Jeff Koch [mailto:[EMAIL PROTECTED] >> >Sent: Thursday, September 06, 2007 11:49 AM >> >To: toaster@shupp.org >> >Subject: [toaster] toaster RAID setup >> > >> > >> > >> >Has anyone successfully setup Bill's toaster with SATA RAID? A year or >> two >> >ago we setup a toaster with a two drive 3ware IDE RAID mirroring setup >> and >> >the performance was awful. Maybe it was because we didn't have write >> >caching enabled on the RAID controller or should have tweaked the >> kernel >> >settings. >> > >> >I looked at Bill's proposed setup for an ISP but we're just trying to >> do >> >this for a single server setup. The only solution we've been able to >> come >> >up with in the past is to have a single small drive for booting, >> /var/qmail >> >and /var/logs and run SATA RAID for /home/vpopmail and everything else. >> But >> >we'd really like to have RAID running for the qmail queue since that's >> what >> >beats the hell out of a hard disk. >> > >> >Any recommendations or experiences anyone? >> > >> > >> > >> >Best Regards, >> > >> >Jeff Koch >> >>Best Regards, >> >>Jeff Koch, Intersessions > > Best Regards, > > Jeff Koch, Intersessions > >
