Hi all What is the best strategy to add another storage to an existing virtual mail system ? Move some domains to the new storage and create symlinks ? Switch to dovecot hashing ? But in this case what is the easy-east way to migrate ? Thanks for any suggestions or tips !
On 4 Jul 2012, at 21:01, Adrian Minta wrote:> What is the best strategy to add another storage to an existing virtual mail system ? > Move some domains to the new storage and create symlinks ? > Switch to dovecot hashing ? But in this case what is the easy-east way to migrate ? > > Thanks for any suggestions or tips !Are you using Volume Management (VLM) on the system, or do you have regular partitions mounted? Is there any RAID or other factors to consider . . in fact, a few details about your system might help :) ~ James.
Quoting Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl>:>> I think there are optimal situations where any configuration looks >> good . . How often can a real-world disk actually deliver the 6Gbs >> when only a minority of disk reads are long sequential runs on the >> platters? > none of hard drives can saturate 1.5Gb/sThere are many disks out that do 150-200MB/sec, easily exceeding 1.5gb/s speeds.
On 7/8/2012 8:27 AM, Patrick Domack wrote:> > Quoting Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl>: > >>> I think there are optimal situations where any configuration looks >>> good . . How often can a real-world disk actually deliver the 6Gbs >>> when only a minority of disk reads are long sequential runs on the >>> platters? >> none of hard drives can saturate 1.5Gb/s > > There are many disks out that do 150-200MB/sec, easily exceeding 1.5gb/s > speeds.There are a few SAS drives that can saturate a 150MB/s link, such as the Seagate Cheetah 15k.7, which can sustain 204MB/s streaming read on the outer tracks. But, again, streaming rate is irrelevant to mail storage. What matters is random seek latency. And the faster the spindle, the lower the latency. Thus 15k Seagate SAS drives are excellent candidates for mail store duty, as are any 10k or 15k drives. -- Stan
> is random seek latency. And the faster the spindle, the lower the > latency. Thus 15k Seagate SAS drives are excellent candidates for mail > store duty, as are any 10k or 15k drives.definitely not counting by $/IOPS rate. even worse looking with $/GB which is more important unless you make <1GB mail account.
On 7/8/2012 5:16 PM, Matthias-Christian Ott wrote:> On 2012-07-08 23:29, Stan Hoeppner wrote: >> On 7/8/2012 8:27 AM, Patrick Domack wrote: >>> >>> Quoting Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl>: >>> >>>>> I think there are optimal situations where any configuration looks >>>>> good . . How often can a real-world disk actually deliver the 6Gbs >>>>> when only a minority of disk reads are long sequential runs on the >>>>> platters? >>>> none of hard drives can saturate 1.5Gb/s >>> >>> There are many disks out that do 150-200MB/sec, easily exceeding 1.5gb/s >>> speeds. >> >> There are a few SAS drives that can saturate a 150MB/s link, such as the >> Seagate Cheetah 15k.7, which can sustain 204MB/s streaming read on the >> outer tracks. >> >> But, again, streaming rate is irrelevant to mail storage. What matters >> is random seek latency. And the faster the spindle, the lower the >> latency. Thus 15k Seagate SAS drives are excellent candidates for mail >> store duty, as are any 10k or 15k drives. > > This is simply not true. SATA SSDs (~0,66 ?/GB) are as expensive as the > 15k Seagate SAS HDDs (0,63 ?/GB), but definitely faster.First, this sub discussion in this thread has been dealing strictly with mechanical storage, and that was intentional. Now you've injected solid state storage, and in the process you first disagreed with my statement, then agreed with it. Apparently you didn't realize you did so. Would you please clarify what I stated that is "simply not true"? You comment WRT SSD doesn't prove anything I said to be untrue. Quite the contrary, you reinforced my statements. -- Stan
On 9 Jul 2012, at 10:41, Wojciech Puchar wrote:> Many people just want to be proud, or want to make things expensive so their clients are proud. but not always it's like that.You go on a bit about "pride in complexity" . . What you fail to understand is that many highly intelligent, experienced, very able engineers build systems that are as complex and as large as they _need to be_ and just because you don't deal with such large systems doesn't make everyone else wrong. (Okay, I know, some people are proud, and some people do make bad decisions about large complex systems -- but you make the mistake of assuming everyone does.) Just my 0.02 -- hope it helps.
Le 10/07/2012 08:13, Robert Schetterer a ?crit :> Am 09.07.2012 21:41, schrieb Reindl Harald: >> in these environments you find near to zero SATA >> only few people these does are doing bare metal installs in days >> where hardware supported virtaliziation has nearly zero overhead > Hi Harald, that simply not true > i have thousends of mailbox users on sata stores > since years ,without any problem, you should learn that > things that might fit at your place, are not the ultimate > answer to everything >Would it be possible to close this thread from Dovecot mailing-list ? Please setup mailing-lists pros-cons-Reindl or pros-cons-sata instead Thank you very much