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  • 0 posts edited
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  • 9 votes cast
Jun
11
comment How does the DNS protocol switch from UDP to TCP?
Case (d) may be a wise choice if the query contains multiple "questions" (addresses to resolve). If you need to resolve 100 addresses, you're not going to be able to fit the response in a single UDP packet.
Jun
11
awarded  Yearling
Jun
9
answered How can you tell what a server actually does?
May
18
comment How can I create one large partiton over two drives in CentOS?
@Vality: I know how RAID-0 works, that is exactly why I'm arguing for a non-striped alternative. That's especially relevant here as the read performance of RAID-0 isn't needed for backups (which is mostly writes)
May
18
comment How can I create one large partiton over two drives in CentOS?
@Mike: I don't read in the answer that RAID 0 is desired, and it's a bad idea for the reasons you indicated. But how else do you tell Linux to store files on one of two disks/partitions? It's of course unavoidable that you lose a file when the disk it's on crashes and you have no redundancy. The problem with Linux LVM RAID is that apparently it also loses the files on the good disk. That wouldn't be acceptable if it was designed today; it seems the behavior is tolerated only because RAID-0 is ancient.
May
7
answered Link aggregation (LACP/802.3ad) max throughput
Feb
13
comment Removing an (apparently) infinitely recursive folder
@Brian: Simple: a batch file that 1. creates Folder1 and 2. recursively copies an entire directory tree to that Folder1\ . Now watch what happens if Folder1 is created in the tree to be copied.
Feb
13
comment How to protect against loss of server on a budget
I'm not saying that failures are fully uncorrelated, but 1+1 redundancy in theory should give you two extra nines for twice the cost. You suggest the cost for two extra nines is somewhere between 9 times and a 100 times. 2x versus ~30x is a huge difference.
Feb
13
comment How to protect against loss of server on a budget
@symcbean: The problem is that a RAID-5 rebuild requires reading all data of all remaining disks. That's a fairly long operation (hours if not days). A cheap RAID-5 system may have a 9+1 setup using desktop drives. All of those 9 disks will be stressed beyond design limits in a RAID rebuild. Failure is then to be expected, in fact.
Feb
11
comment “Mandatory” free space on a SAN?
@TomTom: That calculator actually says 100% chance, if you put in the WD2001FYYG error rates. I think you left the error rate setting at the default (which is the worst rate, for desktop drives)
Feb
11
comment “Mandatory” free space on a SAN?
@TomTom: If you think it's simple mathematics, please do answer the question showing the math. My napkin math says the array is stable if reading 13*2TB to rebuild a degraded array is unlikely to fail. Raid 6 of course is better, that is stable if the rebuild is unlikely to encounter a double fault.
Feb
2
comment Why can't MX records point to an IP address?
@MichaelHampton: I MUST have misunderstood your response to Zenexer ;)
Feb
2
comment Why can't MX records point to an IP address?
@MichaelHampton: If an MX record SHOULD contain a host name instead of an IP address, then an MTA MUST accept an IP address. Hypothetically, if an MX record MUST contain a host name then an MTA SHOULD accept an IP address. That's how RFC's work. The counterparty to a "SHOULD" implementation advice may optimize on the assumption the advice is followed, but that's pretty much all you can do with it.
Jan
26
comment Users with Google's IP address. How is it possible?
This might become even more common as IPv6 becomes popular, and people use IPv6-to-4 proxies. If you're going to geo-target, do support IPv6 and do not make too many assumptions on the nationality of mobile phones.
Jan
19
comment What are the differences between consumer grade SSDs and the much more expensive enterprise SSDs?
Keep in mind that companies will only differentiate if it means real savings. "Worse firmware" means developing firmware twice, and that's more expensive. If the enterprise firmware works on consumer-line products, then ship it. Less warranty, OTOH, is a straight saving.
Jan
19
comment What are the differences between consumer grade SSDs and the much more expensive enterprise SSDs?
Even HDD's have Error Correction Codes nowadays; the reliability would be abysmal otherwise. Even the cheapest USB flash is likely to have ECC. Simple reason: using ECC is actually cheaper, as you can cram more bits in that way. In particular, you can use MLC flash on designs that otherwise would only work as SLC.
Nov
27
comment Windows Command SC, how to check errorlevel
You can always obtain the errorlevel; it's virtually impossible for a program not to have one. But it is very well possible that the errorlevel is always 0. Having non-zero errorlevels is special.
Sep
24
comment Why should iscsi traffic be isolated?
That's by design - QoS lets non-timesensitive data wait for more urgent data such as iSCSI traffic.
Sep
24
comment Why should iscsi traffic be isolated?
That's an argument for QoS. Would you also argue in favor of isolating VoIP traffic?
Jul
23
comment del *.txt removes also file.txt_backup
Ow, turns out the MSDN doc is incorrect when it states that ? matches a single character. It also matches zero characters.