In article , Tim Watts writes
None. A 16GB compact flash card in a SATA-CF adapter. Total cost about 13 quid.
Not as quick as an SSD, but all it needs to do is boot the OS and write log files. Data is stored on the 4 2TB drives in the front bays.
no idea
nope, since I rather doubt the CF would recognise the command :-)
Only for older SSDs. Modern ones self-manage and don't need the TRIM command.
On Thursday 17 October 2013 12:53 Mike Tomlinson wrote in uk.d-i-y:
Fair enough - I assumed it was an SSD in HD format - !
Question though - how can the modern ones possibly know what the OS has released to it's filesystem's free block/extent list without the TRIM (etc) commands being sent.
This is certainly a problem with the EqualLogic NAS I have at work - as VMWare ESXi 4.1 does not know how to pass TRIM (etc) commands down, (well, it didn't last time I checked), deleting stuff from LUNs does not allow the SAN to actually see any free space in its thin provisioned file systems. To do that, I have to migrate all the VMs off a particular LUN and tell the SAN to actually deleted the whole thing.
I would imagine a similar problem remains with SSDs - it cannot effectively move stuff around to manage wear-levelling as it does not know that free space at the OS level is actually free space - which when you've touched every block address, kind of limits its options.
Unless it scans for blocks of all zeros and kicks them out using a sparse-file approach?
That would be the case for mine (the spec of these Microservers does seem to evolve).
So get a PCIe x1 ethernet card for the WiFi router and a PCIe x16 MiFi. Can't think that the PCIe x1 is going to limit things in the real world and over WiFi ...
They can't.
They have more flash memory than is exposed as disk blocks. This means you can never fill them up, so they always have space to do internally generated erases. You can help them by issuing TRIM yourself, but it's actually somewhat more difficult than just firing off TRIMs each time a block is freed by the filesystem, because TRIM commands issued over the bus can take a long time and thus interfere with performance, and part of the object here was to improve performance, so it can easily backfire. You need a filesystem which knows how to manage passing TRIM requests down to the SSDs. Ideally you coalesce TRIM requests and keep them held back until there's no queue of data requests for the drive (but you must then handle the case where a TRIM gets reordered behind a subsequent write to the same block). If you don't have a filesystem designed to handle this correctly, it's often better not to try and let the drive do it by itself. This is also heavily device dependant, and SSDs are still a rapidly evolving technology.
On Thursday 17 October 2013 17:03 Andrew Gabriel wrote in uk.d-i-y:
I can see how that works...
Ah - fstrim doesn't seem to - perhaps it fires in small batches - or I'm just not noticing because linus is so good at caching.
The last wisdom I read was fstrim was better that mounting ext4 with the discard option for exactly the reason that by its very nature, fstrim was a batched infrequent operation.
Fascinating stuff! Thanks for that. I'll say they are evolving - half of what you just said obsoleted a fairly recent blog I read the other day!
The other half was a most interesting insight that wasn't covered in the stuff I read.
It depends on using common sense....
Not many people buy servers as Christmas presents.
PCIe x1 gen 2 is 5Gbps and x16 is 80Gbps. Not sure you need a 100gig ethernet card to walk to the wifi... (and it wouldn't have the right plug anyway)
Theo
Read carefully, noting the difference between W and M. B-)
The OP says he can only find MiFi cards in the x16 variant but already has that slot occupied by an ethernet card for WiFi. Seems very obvious to me to get a x1 ethernet card for the WiFi and the x16 MiFi one and just shove in the appropiate slots...
To me 'MiFi' is a 3G to wifi router - which is usually a pocket-sized thing, not a PCIe card. And that's what Google makes of it too. Some of these things have wired network ports (so they look more like domestic routers, which is essentially what they are) which you could conceivably connect to via an additional ethernet card. But a 100Mbit card would do just fine.
So I have no idea what they mean by 'x16 MiFi' cards.
Theo
As the OP, I found your suggestion very helpful, and have been looking for PCIe x1 ethernet cards. Amazon have some very cheap cards, and a slightly more expensive Intel card, which I'm planning to get.
I think I used the wrong term when I wrote about a MiFi card; I meant a card like the HuaWei EM820U Mini PCI-E, allowing GSM/GPRS access to the server. However, I'm not sure if a device like this would provide a backup link to the server if the DSL connection fails, which is what I am looking for?
I think someone posted that they had such a backup system in place, but I cannot find any reference to this.
Facts are better ...
Not sure how much salt to take with a website that uses 'fool' as its domain name, but in a brief search it's the only relevant page of stats that I was able to find - note the significant bumps over every Q4 in the World Wide PC sales chart:
As this thread of itself proves, servers are bought domestically as well as commercially, therefore it follows that more of them are likely to be sold over Christmas.
Think I got an Intel one from eBuyer. Bought OEM so no fancy packaging to give me a visual aid to remembering.
Well I suppose that isn't really a MiFi as it doesn't have the WiFi side to link to the 3G side. Looking at the pictures though the connector looks ordinary PCIe x1 rathe than the larger PCIe x16. But this is outside my comfort zone. B-)
Well it provides a data link so if you have the right drivers for it and some relaible method of doing the failover and recovery i guess it ought to work.
But bear in mind that feeder losses might be significant to get a decent 3G signal to it. A seperate ethernet connected "3G access box" might be easier to install both from the drivers POV and physical. Bung it up in the loft or window sill on the right side of the house etc...
You do like digging a hole for yourself, don't you? I can;t even be bothered to point out the multiple flaws in the above.
In message , Andrew Gabriel writes
Yeah, but in the case of the Microserver, the cashback caried on evenw hen they ahd new moderls out. I'm sure it's spends more of it's time on cashback offer than not.
It's a *mini* PCIe card. That's a whole different ballgame from PCIe. While mini PCIe carries a 1x PCIe channel, it also carries USB and most 3G cards only use that and don't touch PCIe. Standard PCIe doesn't carry USB.
Essentially this is a USB wifi dongle designed to fit internally in a laptop, often called a 'WWAN' card. You'd be better off using a USB dongle. This card has no built-in antennas, so you'd have to provide them yourself, while a dongle has an antenna inside (and usually a cover you can pop off to reach a socket should you want to connect a more powerful one). Plus you can put the dongle on the end of a cable and locate it somewhere with better signal.
"It's just a matter of software". Setting everything up to do it will depend on what the PC is running. In other words, it doesn't do it automatically, you have to program that yourself.
I'd go with the router idea - far less faffing about getting the failover to work.
Theo
The predictable reply. No, you're just not worth it.
Meant to type 'USB 3G dongle' here...
Theo
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