need partitioning advice

inky

inky

Hello everybody,

I replacing my own web/mail server with the leased one, sites grow up, so need more power. Here what i got - 24GB of RAM, 2x300GB SAS HDD hardware RAID 1 on adaptec 5405 and 120GB SSD. I stuck on partitioning, just cannot decide what to place on SSD.

Whats gonna be better to place on SSD - SWAP partition, temporarily directory (/tmp), exim spool directory ? I wanted to place MySQL on SSD, but its not mirrored, so i better leave it on raid.

And second question about SWAP size - thinking about 4-8GB max, but some people doing it 2x memory - it will take 48GB of hdd space, that's too much i think. My old server with 4GB of RAM only used 256kb from out of 1GB swap partition aligned for all 8 years history.

Thank you in advance.
 
Use ZFS and place the ZIL (Zfs Intent Log) and L2ARC (read cache) on the SSD. IMHO you have enough space to place your swap on the SSD too. Do some reading to determine L2ARC and ZIL size you will need. Some argue that ZIL is not really needed, but why not take full advantage of the hardware you have. Not sure, but I also think SQL could benefit from ZIL.

Swap size depends on what you intend to do with the machine also. Are you going to do anything with it that will max-out the RAM? If (and probably) not, the swap you need is just for "fallback". In that case 5G should be sufficient. Actually, the less RAM you have the more swap you will need. Some how-to's describe placing the swap as a ZFS dataset, but I have found ZFS-only swap to have lock-up problems.

This way, you can keep your HDD partition table as RAW and give ZFS the whole disk to do with it as it pleases. If you have any space left on your SSD, I'm sure we can figure out some additional performance-increasing measures, like placing the SQL cache on the SSD for example. The other partitions (/var /tmp /usr) ZFS will take care of - read the FreeBSD wiki about "root on ZFS".

Synopsis: Place the services which will benefit the most from speed on your fastest drive (SSD)
 
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