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visits member for 2 years, 11 months
seen Aug 14 at 2:08

UNIX noob, enterprise storage expert


Aug
11
comment How big are my disk arrays?
Terminology matters here- a SAN is technically the entire network for the storage- all the switching, storage controllers, and client hookups (like HBAs and blade interconnects). A JBOD can live in a SAN, but rarely does. A JBOD is almost always directly attached to a server, and relies on the server's RAID card to control the disks. A more commonly seen setup is where the disk controller has its own raid management system and provides virtual disks (LUNs) to whatever servers connect to it.
Aug
11
comment Fibre channel long distance woes
It's recommended any time you can use it- as far as I can tell, it's a question of how much interference an idle frame causes its SFP to create.
Aug
3
comment Fibre channel long distance woes
I didn't see this when it was asked, unfortunately. I can't tell you for sure that this would help, but if you're using idle-idle fillwords, you're sending a lot of light. This means that each unused frame is pulling a lot of power and generating a lot of heat on the SFP, I think. Changing the fillword to some other mode (I use mode 3, but I have a different switch and SFP) might allow you to push more throughput with fewer errors.
Aug
1
comment What is the difference between a HBA card and a RAID card?
Most HBAs don't do RAID. Most RAID cards won't let you connect anything but a storage device. HBAs are normally just to let you connect to SAS or FC. Raid cards are normally just for connecting local drives.
Jul
31
comment EMC VNXe GNU Source Code
That makes more sense, now that I've read that. In your situation, there's nothing wrong with voiding the warranty since it'll help hold things together until the correct solution comes on the floor.
Jul
31
comment EMC VNXe GNU Source Code
@Metalshark You didn't say that you wanted to review their code for security. You said you wanted to void the warranty because you were tired of waiting on hold. What you are trying to do with the source code absolutely matters, when determining whether this question is a fit for the site or not. That said, even your example of checking source code for security is probably a better fit on the security SE than this one.
Jul
31
comment EMC VNXe GNU Source Code
This is a Q&A site for professional systems administration, and hacking and voiding the warranty of an expensive storage machine is not something that a professional systems administrator does.
Jul
31
comment EMC VNXe GNU Source Code
Pretty sure that would void the warranty. If you don't like the way the storage is supported (and believe me, I get it- I'm curb stomping all my EMC at the first available opportunity), you make noise or just deal with the difficulty. You don't start logging in with an account that's only available to EMC employees.
Jul
31
comment EMC VNXe GNU Source Code
And what would you do with the service shell that you can't do with an administrative user account?
Jul
31
comment EMC VNXe GNU Source Code
messner, if I remember correctly, is the password for engineering mode in the clariion. That doesn't sound like what you're looking for, though...
Jul
31
comment EMC VNXe GNU Source Code
What temporary password system is this? What would it allow you to do?
Jul
24
comment RAID-5: Two disks failed simultaneously?
Raid levels all have their use. Raid 10 throws half your capacity out the window, but doesn't make anything calculate parity. A good controller will calculate parity well enough that it isn't that slow, and will have a cache that hides the write penalty even more.
Jul
24
comment Can a NetApp disk array be used as a JBOD?
Could be both- disk for sure, but old FC cabinets will have some sort of ghetto switch that may also have been designed to avoid use this way.
Jul
24
comment RAID-5: Two disks failed simultaneously?
@Wardy I think I misread your comment- absolutely, having your data in another set of disks in another chassis is better than local raid.
Jul
23
comment RAID-5: Two disks failed simultaneously?
Whatever caused it to freeze his rebuild would still be in there, potentially. Sometimes bad sectors can't be recovered with a block copy. That said, to get this server back online, the professional solution is to recover from a recent backup and not spend time trying to do low-level data recovery which may not even work.
Jul
23
comment RAID-5: Two disks failed simultaneously?
@Wardy, wouldn't raid 6 give you that?
Jul
22
comment RAID-5: Two disks failed simultaneously?
I don't see the write penalty- random writes are cached, and sequential ones don't suffer as greatly from it.
Jul
3
comment Send interactive zoning commands to Brocade switch
Thanks :) I'm considering that program option, but it's a shame that Brocade makes this so hard.
Jul
1
comment Send interactive zoning commands to Brocade switch
I don't have screen installed on AIX... but reading about it, it certainly seems like something worth fighting to get. In the meantime, though, is there anything in the world of sessions, pipes, and redirection that can get me where I need to be?
Jun
6
comment Why would Linux VM in vSphere ESXi 5.5 show dramatically increased disk i/o latency?
I'm not sure, to be honest. I normally deal with it at a storage controller level, but this is on an internal disk.