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I recently purchased a used server (the type that fits into a rack, rather than a free-standing machine). One nice feature, is rather than having to open up the cover and unscrew the harddrives, this machine has eight "easy to use" caddies on the front.

How can I tell if this server unit supports hot-swapping drives? Do I need to look up the machine's specifications, or can I run a command from inside Linux to detect this?

In my particular case, the product number I can find is for the chassis, a SuperMicro model 825-7, and the output from several hardware related Linux commands can be found in this repository: GitHub: IQAndeas/computers: Austere Armadillo.

Keep in mind, I was hoping there was a solution which does not require looking up the specific model number, but can be used regardless of which server you are on.

IQAndreas
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    There is a third option, to just try removing one of the lines while the server is running. I'm just worried about "Well, turns out it _doesn't_ support hot-swapping. I guess that 1GB drive is ruined now." – IQAndreas Sep 02 '15 at 00:06
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    Providing pertinent details, *like the make and model of the server*, would help us help you. Otherwise, there's no deterministic way to provide you the information you're seeking. – ewwhite Sep 02 '15 at 00:11
  • @ewwhite I edited the question with the details I could find, however, as I said in the question, I left the question open-ended as I was hoping this question could help more than just me. – IQAndreas Sep 02 '15 at 00:16
  • I'm sure your server supports hot-swap, in that your drives or SAS/sata controller(s) won't melt if you pull the drives out and insert them again. What's more interesting is really, is there a HW raid controller there ? Is it software raid ? Is it running a RAID level for which you can tolerate drive loss ? Are you using some other form of storage aggregation which is amenable to "hot swapping" drives. – Kjetil Joergensen Sep 02 '15 at 01:13
  • @KjetilJoergensen That's all the information I'm trying to find out, I just received the server, and have no idea about the capabilities. And I'm having the damnedest time even getting into BIOS. ;-) – IQAndreas Sep 02 '15 at 01:26

2 Answers2

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Grrrr... I hate Supermicro... and white box servers in general - There's no consistency in model numbers or parts. If HP, IBM, Dell, etc., we would be able to look at your server model number and say, "yes, this supports feature X".

For you, this is going to depend on the controller inside the server, as well as how the SAS backplane is connected.

Please provide the information from lspci on the server. Perhaps df -h and lsscsi or cat /proc/scsi/scsi.

This will give us some RAID controller information if (present) and perhaps some information to proceed with.

Edit:

Your server supports hot-swap.

From: https://github.com/IQAndreas/computers/tree/master/austere-armadillo

This is an older 2007/2008-era server.

Here's your RAID controller's logical drives.

[2:0:0:0]    disk    AMCC     9690SA-8I  DISK  4.08  /dev/sda 
[2:0:1:0]    disk    AMCC     9690SA-8I  DISK  4.08  /dev/sdb

and

Host: scsi2 Channel: 00 Id: 00 Lun: 00
  Vendor: AMCC     Model: 9690SA-8I  DISK  Rev: 4.08
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi2 Channel: 00 Id: 01 Lun: 00
  Vendor: AMCC     Model: 9690SA-8I  DISK  Rev: 4.08
  Type:   Direct-Access                    ANSI  SCSI revision: 05

It's a 3Ware 9690SA-8i, which uses the 3w_9xxx kernel module in Linux. You have a pair of disks in RAID 1 and four disks in RAID 5. These are SATA disks, so I recommend reconfiguring them to RAID 1+0, giving you 2TB of usable space on the larger array. You'll be able to do this from the BIOS by pressing Alt-3 during the RAID controller's initialization. The manual for the RAID controller is here.

enter image description here

ewwhite
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  • The server definitely uses RAID; it has 2x320GB drives and 4x1TB drives, yet only has 298GB and 2.7TB of storage, respectively. Since there is no operating system installed (the harddrives are wiped) I'm assuming it's a hardware RAID. – IQAndreas Sep 02 '15 at 06:48
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    When you do find the information you need, rather than just give the answer, to benefit others, I would appreciate it if you included in the answer which values you were looking at to get the answer. – IQAndreas Sep 02 '15 at 06:53
  • I think he before you had the extra information edited in. Back then, the answer was incomplete. Now, it is perfect. – IQAndreas Sep 02 '15 at 07:13
  • Just to summarize and clarify a few RAID-related unknowns: I have two more empty slots. Does all this mean while the server is running, I can insert one more SATA harddrive (unrelated to any of the RAID drives) into an empty slot, and it would appear, able to be mounted just fine, something like a USB drive would act? – IQAndreas Sep 02 '15 at 07:18
  • @IQAndreas No. It would need to be configured into a _Logical Drive_ or _Virtual Drive_ using the 3Ware command line utility (`tw_cli`) or from the BIOS. – ewwhite Sep 02 '15 at 07:20
  • Ah, so drives are only hot-swappable if they (or at least their sizes) are already "known" and "registered" by the server? – IQAndreas Sep 02 '15 at 07:23
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    The disks can't be presented to the OS unless they are in _Virtual Drives_. That's all. – ewwhite Sep 02 '15 at 07:26
  • What does your dislike of Supermicro have to do with answering this question. It is simply noise and distracts from your actual answer. – Mark Booth Jul 02 '18 at 14:19
  • @MarkBooth it’s relevant because these aren’t problems people should have _today_ with modern equipment. – ewwhite Jul 02 '18 at 17:53
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If you can change drives or move them around with just your fingers and no tools, then it supports hotswap. If it's manufactured after about 2006, it supports hotswap. If it uses electrical utility power instead of coal, then it supports hotswap. Get back to work.

Billy left SE for Codidact
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