21,705 reputation
12449
bio website ripple.com
location Oakland, CA
age 45
visits member for 3 years, 4 months
seen 2 days ago

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


Mar
10
comment Problems with time correction on Debian
The system does not assume that everyone using it is in the same time zone the system is in.
Mar
10
comment Configuring multiple servers to share one static IP using subdomains
Access them with what? A browser? Is this an HTTP question?
Mar
9
comment Software RAID setup questions
@jdickson: If you are worried about losing your data, you need to back it up. RAID is about minimizing and avoiding down time, not protecting against data loss.
Mar
9
awarded  Nice Answer
Mar
9
answered Software RAID setup questions
Mar
9
answered Moving SSL Certificate to new server
Mar
8
answered every email marked as SPAM or not even delivered?
Mar
8
comment every email marked as SPAM or not even delivered?
It is marked as spam by who or what? You forgot to tell us what this problem is about.
Mar
8
comment Different results from GnuPG and OpenSSL when using AES256 encryption
Both of these tools internally use AES256, but their output formats are completely different. Can you be more specific about what you're trying to do? Do you really need deterministic encryption where the same input always produces the same output?
Mar
7
comment using a gre tunnel as default route
You cannot allow a tunnel to become the route to its own destination or the tunnel implodes.
Mar
7
comment Why does RAID5 with an odd number of data disks have poor write performance
let us continue this discussion in chat
Mar
7
comment Why does RAID5 with an odd number of data disks have poor write performance
@psusi: You're taking us in circles. Right, we all agree on that. Again, the question is: After this aggregation, do you think more writes will be an even multiple of 2MB or more writes will be an even multiple of 2.5MB?
Mar
6
comment Why does RAID5 with an odd number of data disks have poor write performance
@psusi: I don't understand why you keep taking us in circles. Yes, there's aggregation. But after aggregation, if the write is an even multiple of the stripe size, no read before write is needed. Otherwise, a read is needed before the write. Do you think more writes will be even multiples of 2MB or will be even multiple of 2.5MB? If more writes are even multiples of 2MB than 2.5MB, then a RAID with a stripe size of 2MB will perform better since less data will need to be read in order to write.
Mar
6
answered Do CDMA based time servers passively read timing information from the cell network?
Mar
6
comment Fast, but extremely spikey network transfers
I don't see any evidence that it's not pulling the data off the drive constantly. Do you have any reason to suspect that during the times when the network traffic is lower, the disk I/O throughput is also lower? (Imagine if you're receiving pumpkins one at a time and sending them out in trucks of 1,000. You'll see a pause, then a truck of 1,000, then a pause, then a truck of 1,000. But pumpkins are arriving at an even rate. More trucks wouldn't make pumpkins arrive faster nor does pauses between trucks indicate pauses in arrival.)
Mar
6
comment Why does RAID5 with an odd number of data disks have poor write performance
@psusi: The reason would be that fewer reads are required to write because fewer partial stripe writes are necessary. Fewer partial stripe writes are necessary because after aggregation, at the RAID layer, more writes will be even multiples of 2MB than of 2.5MB.
Mar
6
comment Why does RAID5 with an odd number of data disks have poor write performance
@psusi: That's nonsense. Whether an operation is sent to the drive as a pure write or a "read-then-write" depends on whether it can be aggregated to a multiple of the stripe size. So that aggregation has to be done before drive level, at the RAID level.
Mar
6
comment Linux: find total memory in use…without free(1) or /proc
By memory, you mean physical memory, right? But what precisely do you mean by "in use"?
Mar
5
answered 2 BGP Upstreams, One sending default route, another Full Table
Mar
5
comment Is it possible to generate RSA key without pass phrase?
Your command line tells openssl to encrypt an existing key. That sounds like something other than what you want.