Jim Klimov
2013-10-02 09:52:45 UTC
Hello all,
I believe it is valid to say that the most important quality of SSDs
for a small-box ZFS usage (rpool, zil ffor data pool, l2arc) is their
reliability, then size as fit for the rpool and caching of a particular
data pool, low price (provided that the constraints above are met) and
performance (for a low price expected substellar, though above hdds).
Reliability involves good wear-leveling chipsets, which should maximize
the total writeable volume and/or time until total device death given
the technology of chips (slc, mlc, emlc, etc.) and element size (nm),
minimize block errors (io errors or garbage upon read), and powerloss
protection (do save cached sync writes, don't sprinkle garbage over
existing data).
I believe the latter aspect - powerloss protection - severely limits the
choice in both cheap and "almost enterprise" series. At least,
this is important for ZIL and rpool, less so for L2ARC.
For commercial servers i was looking at intel dc3700 or dc3500 lineups,
which tout reliability and a long warranty, but are a bit pricey and
maybe overkill for a home enthusiast (store photos, serve a scratch area
to edit them over cifs/nfs, store backups of the home zoo of pc's,
occasionally run some compilations or vm's).
Is there anything of similar quality and reliability, but cheaper
(perhaps smaller and slower) that list members can recommend to use
at home without worries that data/OS would be more reliably served
without SSDs in the box (i.e. something not crappy)?
Also, what sizes should be reasonably set aside for zil (mirrored)
and l2arc (striped) for a 4*4tb raidz1 (probably) pool on a planned
maxed-out HP n54l with 16gb ram and an LSI9211-based HBA? I guess,
based on RAM size, there is some limit after which more L2ARC won't
do any good anyhow? :)
Thanks,
//Jim Klimov
Typos courtesy of my Samsung Mobile
I believe it is valid to say that the most important quality of SSDs
for a small-box ZFS usage (rpool, zil ffor data pool, l2arc) is their
reliability, then size as fit for the rpool and caching of a particular
data pool, low price (provided that the constraints above are met) and
performance (for a low price expected substellar, though above hdds).
Reliability involves good wear-leveling chipsets, which should maximize
the total writeable volume and/or time until total device death given
the technology of chips (slc, mlc, emlc, etc.) and element size (nm),
minimize block errors (io errors or garbage upon read), and powerloss
protection (do save cached sync writes, don't sprinkle garbage over
existing data).
I believe the latter aspect - powerloss protection - severely limits the
choice in both cheap and "almost enterprise" series. At least,
this is important for ZIL and rpool, less so for L2ARC.
For commercial servers i was looking at intel dc3700 or dc3500 lineups,
which tout reliability and a long warranty, but are a bit pricey and
maybe overkill for a home enthusiast (store photos, serve a scratch area
to edit them over cifs/nfs, store backups of the home zoo of pc's,
occasionally run some compilations or vm's).
Is there anything of similar quality and reliability, but cheaper
(perhaps smaller and slower) that list members can recommend to use
at home without worries that data/OS would be more reliably served
without SSDs in the box (i.e. something not crappy)?
Also, what sizes should be reasonably set aside for zil (mirrored)
and l2arc (striped) for a 4*4tb raidz1 (probably) pool on a planned
maxed-out HP n54l with 16gb ram and an LSI9211-based HBA? I guess,
based on RAM size, there is some limit after which more L2ARC won't
do any good anyhow? :)
Thanks,
//Jim Klimov
Typos courtesy of my Samsung Mobile