Hi, Op 4-8-2010 17:40, Curtis Maurand schreef:
On 8/3/2010 11:15 AM, Eugen Leitl wrote:
You could probably mitigate some of the writes to disk by having the logging sent to a syslog server elsewhere inside the house that is using traditional write media. That should lengthen the life of the SSD at least until the next generation of SSD comes along that has no write limitations.
Really, the whole SSD write issue is not too relevant based on the size of your SSD drive/CF card.
It is widely known that flash has limited write cycles, 10.000 is common for current MLC flash.
So if you have a 8GB flash card, of which 200MB is allocated by a pfSense image that leaves ~7.5GB free unused cells. The wear levelling in Flash Drives and CF cards will use these unused cells to spread the writes.
What this effectively means is that the with 10k write cycles per cell the actual longevity is multiplied by a factor of 7.5.
The situation with even larger ssd drives is even better. You install pfSense to a 40GB Intel X25-V, which effectively means that you won't live long enough to see it fail.
Do note, that if you ever write the device from start to end that this negates the wear levelling. It then only has the spare cells on the drive or card to remap blocks (~7%).
On that note, my much used 1GB lexar 133x CF card I bought when I joined the pfSense project in late 2005 is still fine after running pfSense versions from pre 1.0 to current 2.0BETA4. It's been reflashed a lot, and it's always been running a full install. Because then I can gitsync the installation.
According to the pessimists the card should have stopped working atleast 3 years ago. Luckily the world isn't so grim.
The CF cards I purchased with a few Alix systems at work though, they stopped working within 3 months. That was with the embedded image that doesn't write to the CF. Which leads me to believe they were exceptionally bad.
The Kingston 8GB premium cards in there appear to be perfectly fine. It also seems to have rid them from lockups.
Regards, Seth --------------------------------------------------------------------- To unsubscribe, e-mail: support-unsubscr...@pfsense.com For additional commands, e-mail: support-h...@pfsense.com Commercial support available - https://portal.pfsense.org
