21,018 reputation
12247
bio website ripple.com
location Oakland, CA
age 44
visits member for 2 years, 11 months
seen 2 days ago

I am Chief Cryptographer at Ripple Labs and one of the architects of the Ripple payment system.


Feb
8
comment How come the netflow data isn't showing up on the server?
Do you see any flow packets being sent? That will split the problem space in half.
Feb
7
comment Improving TCP performance over a gigabit network with lots of connections and high traffic of small packets
What's the limiting factor? Does your CPU max out? If so, you're barking up the wrong tree. You need to look at what the CPU is doing.
Feb
7
comment Problems with degraded RAID arrays
@donjon That's only true of physical sectors on the drive, which is totally irrelevant because the system only has access to logical sectors. You can use an SSD, reaching the write cap on a physical sector is irrelevant.
Feb
7
comment Killall waiting for response
What do you mean by "there is no response"? Do you mean your killall hangs? Or returns without any output? Or do you mean it appears to work normally but the process doesn't die? Or what?
Feb
7
comment One server is 33% slower than another identical one. How to troubleshoot?
@AngryHacker Which CPU? And what are the temps? (The most likely explanation, I think, is that the slower machine has poor CPU cooling due to a bad fan, improperly mounted heat sink, blocked vent, intake near some other machine's exhaust, or the like.)
Feb
6
comment What is faster hard drive system for a server, SSD, SAS, RamDisk?
If it were me, I'd use an SSD but just make sure the server has lots of RAM. So for practical purposes, it will all be cached in RAM anyway. I'd probably add a cheap hard drive for internal backup, if possible. (In case the SSD fails.)
Feb
6
comment One server is 33% slower than another identical one. How to troubleshoot?
Check CPU temperatures. What CPU is this? (If it's a CPU with an auto-overclock / turbo capability, it could just be natural variation among the CPUs.)
Feb
6
comment High Failure Rate of Large Drives?
I had a similar experience. 16 1.5TB drives. In the first 4 months, 4 hard failed. In the next three years, one soft failed.
Feb
6
comment What would cause a successful file transfer to have checksums not match?
I would start by comparing the two files to figure out what the difference is. It would also help a lot if you posted how you were transferring the files (scp, nfs, rsync).
Feb
5
comment Clock is 10% faster than normal
@Oleander Maybe, but with it not running, how can you tell? By shutting NTPD off, you made it much more difficult to debug.
Feb
5
comment Clock is 10% faster than normal
So ask NTPD what it's doing, what server it's synchronized with, whether it was able to reach it, and so on.
Feb
5
comment Clock is 10% faster than normal
NTPD has sophisticated monitoring that allows you to tell if it's able to community with its peers or servers, which one it has chosen to sync with, whether it actually is in sync, and so on. If you normally run with NTPD on, what's the point of debugging with it off? You should be debugging the configuration you run.
Feb
5
comment Clock is 10% faster than normal
Your question says the NTP daemon is off. If it's on, then how is it configured? And what does its monitoring say?
Feb
4
comment How does a registrar use the nameserver record to point domain name at a server?
In other words, you don't have to do it because your webhost does it for you. Since they're hosting both the web side and the domain's DNS, they automate moving the information about the web hosting to the DNS.
Feb
4
comment Understanding iptables chains in linux (in socket terms)
Pretty much every firewall is also a server of some sort. For example, it may have a web administration interface, meaning it has a web server.
Feb
3
comment Configure a Linux router for fair bandwidth allocation without unnecessary limiting it
Perhaps it should be, but so far as I know, nobody's gone and done it. I don't believe there's any good way to do this right now.
Feb
2
comment Configure a Linux router for fair bandwidth allocation without unnecessary limiting it
@jstarek Assuming that's true, what's the good way to delay ACKs right now?
Feb
1
comment Email Server IP Address is Blacklisted
Did you follow the links in the error messages you got? They should provide explanations.
Feb
1
comment Email Server IP Address is Blacklisted
If that 41.78.60.33 is accurate, you still have no reverse DNS.
Feb
1
comment Terminating a high volume of SSL connections cost effectively on EC2
Are you assuming each of those SSL connections forms a new session? Or are you testing with some level of session reuse? It makes a huge difference.