On 11/2/2016 3:01 PM, Steve Crawford wrote:
> After much cogitation I eventually went RAID-less. Why? The only
> option for hardware RAID was SAS SSDs and given that they are not
> built on electro-mechanical spinning-rust technology it seemed like
> the RAID card was just another point of solid-state failure. I
> combined that with the fact that the RAID card limited me to the
> relatively slow SAS data-transfer rates that are blown away by what
> you get with something like an Intel NVME SSD plugged into the PCI
> bus. Raiding those could be done in software plus $$$ for the NVME
> SSDs but I already have data-redundancy through a combination of
> regular backups and streaming replication to identically equipped
> machines which rarely lag the master by more than a second.
just track the write wear life remaining on those NVMe cards, and
maintain a realistic estimate of lifetime remaining in months, so you
can budget for replacements. the complication with PCI NVMe is how to
manage a replacement when the card is nearing EOL. The best solution
is probably failing over to a replication slave database, then replacing
the worn out card on the original server, and bringing it up from
scratch as a new slave, this can be done with minimal service
interruptions. Note your slaves will be getting nearly as many writes
as the masters so likely will need replacing in the same time frame.
--
john r pierce, recycling bits in santa cruz
