Cyrus mail spool entirely on SSD

[Shawn Bakhtiar]

I actually just migrated our Cyrus (IMAP) server and was looking into this same questions.

I think SSD's are great! Especially in laptops where the drive is susceptible to sudden changes in inertia (in spinners this can lead to physical mechanical damage, but SSD's are immune), not to mention the lower power consumption and heat. However the one thing everyone seems to agree on is that SSDs do have less read/write cycles than their spinner counter parts (especially enterprise grade). The NAND gates that store and retrieve the bits wear out more quickly, than the plater in spinners. Some seem to suggest much more quickly, but I don't think anyone really agrees/knows how much more quickly truth be told. It depends on who's report/article you read, and the way the drive is used.

Given that an IMAP server (or any data store for that matter) can have heavy disk utilization, you may still be best severed by using the spinners (which in a server does not suffer sudden changes in inertia). You could have the OS reside on an SSD for faster boot, etc... but store the data on spinners.

We have about ~150 mailboxes with no quotas. Our old server ran for 8 years using spinners in a RAID 1, with the occasional swapping out of a bad drive (perhaps a handful of times, do to SMART indicating possible failure). The only reason we upgraded to a new server was because we ran out of space, and I wanted to move away from Linux to FreeBSD (insert shameless plug for FreeBSD here).

Our users use the IMAP server more like a file share storing PO, Orders, RMA, Quotes, and all manor of PDFs regarding our industry. Our new server uses spinners in a RAID 5 like our file server (which is still going strong after 8 years with no issues).

We will eventually move our Web, DNS, LDAP, etc.. servers to SSD, but for now I think keeping data stores on spinners is a better option, at least until the technology has time to prove it self at least as reliable under heavy loads.


On Oct 19, 2016, at 11:28 AM, Michael Ulitskiy via Info-cyrus <info-cyrus at lists.andrew.cmu.edu<mailto:info-cyrus at lists.andrew.cmu.edu>> wrote:

Hello,



I have a task to build a mail server with the following requirements:
1. ~ hundred mailboxes with up to 10G of data each
2. several mailboxes that may grow up to 100G each
3. client insists that splitting data into folders is inconvenient to them and so
all/most of that data will likely live inside INBOX
4. it must be as fast as possible, searchable etc.



My question is: assuming cost is not an issue, would it be advisable to put an entire cyrus mail spool on SSD?
I'm thinking about combinining multiple SSDs into RAID10 to further increase performance.



I've googled around and I see people put metadata and caches on SSD, but I haven't found a mention
of using SSD for entire mail spool. Is it a good idea? Bad idea? Terrible idea?
What do you think?



Thanks,
Michael
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