Hi, I've read that ZFS needs "direct control" to the underlying storage, and that often on board sata controller have bad performance (cheap chip...). Also some boards (i.e. Server Intel S2400SC) are only SATA2 (3Gb/s).
So I need a controller expansion board, and a cheap one since there is not need of RAID or BBU or on board cache (ZFS uses plenty of ram / a L2ARC cache on SSD for it).
I've read that the controller it needs to support "JBOD", and I've bought a Adaptec 6805e.
But I've discovered that a) disks need to be initialized before been seen (so adaptec writes some metadata on them... breaks portability to other brand controllers/on board sata channels?) b) in ROM configuration (^A at boot) if set as JBod I've not seen any option regarding controller onboard cache (128MB), so can't disable and/or see if is in writethrough.
Connecting a jbod, ext4 formatted disk to another computer I can access it, though, so the "initialization" seems not to be a real problem.
What I ask is:
a) what controller do you suggest for ZFS that supports 8 disks and is >= 6GB/s? (I need 4 disks for raid10, one SSD for cache/log, one big one for vm backups = at least 6 disks connected)
b) is the Adaptec 6805e set as JBod ok? smartctl -i gives me disk data for each of the /dev/sdX connected (seems ZFS needs to access that info, right?)
Any other tip for my "low cost" server? I.e. Adaptec series 7-8 have "HBA Mode" that AFAIU would be perfect, but they cost around 900 euros, that is too much (I want to use ZFS also to save the money needed for an high end RAID controller with BBU).
Thanks a lot
LAST MINUTE: argh, if I set 6805e ad JBod, the disks are NOT bootable (the controller does not even appear in the MB list of bootable device, while it does if I create a i.e. raid1 volume). This is driving me crazy
So I need a controller expansion board, and a cheap one since there is not need of RAID or BBU or on board cache (ZFS uses plenty of ram / a L2ARC cache on SSD for it).
I've read that the controller it needs to support "JBOD", and I've bought a Adaptec 6805e.
But I've discovered that a) disks need to be initialized before been seen (so adaptec writes some metadata on them... breaks portability to other brand controllers/on board sata channels?) b) in ROM configuration (^A at boot) if set as JBod I've not seen any option regarding controller onboard cache (128MB), so can't disable and/or see if is in writethrough.
Connecting a jbod, ext4 formatted disk to another computer I can access it, though, so the "initialization" seems not to be a real problem.
What I ask is:
a) what controller do you suggest for ZFS that supports 8 disks and is >= 6GB/s? (I need 4 disks for raid10, one SSD for cache/log, one big one for vm backups = at least 6 disks connected)
b) is the Adaptec 6805e set as JBod ok? smartctl -i gives me disk data for each of the /dev/sdX connected (seems ZFS needs to access that info, right?)
Any other tip for my "low cost" server? I.e. Adaptec series 7-8 have "HBA Mode" that AFAIU would be perfect, but they cost around 900 euros, that is too much (I want to use ZFS also to save the money needed for an high end RAID controller with BBU).
Thanks a lot
LAST MINUTE: argh, if I set 6805e ad JBod, the disks are NOT bootable (the controller does not even appear in the MB list of bootable device, while it does if I create a i.e. raid1 volume). This is driving me crazy
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