Ken Schneider wrote:

On 03/03/2016 08:51 AM, Per Jessen wrote:

...

I've been playing with an Intel Compute Stick which has just one USB port. I've attached a cheap USB-hub to add another 3 ports - one for a USB harddrive, one for the wireless keyboard+mouse and one for a wifi dongle. I tried building a kernel (/usr/src/linux on the usb harddrive) with make -j4, but this led almost immediately to a crash/disconnect/io-errors, so I scaled back to make -j1.

I was wondering if I should be worried about the technnical quality of the USB hub?

Absolutely. Make sure the hub you are using supplies its own power or you will have problems with any device that needs more then a little power.

The USB harddrive has its own supply, and the two dongles can't be drawing that much. I was more thinking about dodgy hardware that doesn't do well with concurrent requests? Still, good point about the power, thanks. -- Per Jessen, Zürich (3.4°C) http://www.hostsuisse.com/ - dedicated server rental in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

Greg Freemyer wrote:

Per,

I'm the heavy external drive connected via USB hub user on the list.

Anker brand USB 3 hubs are the only ones I trust. I've bought and discarded 2 other brands.

fyi: My 64GB lab machine currently has about 20 external USB drives hooked up to it. It's been that way for over a week. With the non-Anker hubs I would see USB connection disconnects/re-connects at least once every 24 hours, so I couldn't maintain a long term mount like this.

Thanks Greg, that confirms my suspicion. My hub really was just a cheapo (SFr9 I think), so if it's a little dodgy, I'm not surprised. Compiling the kernel with -j4 produced hiccups every 5 mins.

fyi2: I've never gone past /dev/sdz (ie. the 26th drive in a system) but I'm now close enough to think about it. What comes after /dev/sdz?

The enumeration starts over at sdax: # lsscsi [1:0:0:0] cd/dvd COMPAQ CD-ROM SN-124 N104 /dev/sr0 [3:0:0:0] disk IET VIRTUAL-DISK 0 /dev/sda [3:0:0:1] disk IET VIRTUAL-DISK 0 /dev/sdb [3:0:0:2] disk IET VIRTUAL-DISK 0 /dev/sdc [3:0:0:20] disk IET VIRTUAL-DISK 0 /dev/sds [3:0:0:21] disk IET VIRTUAL-DISK 0 /dev/sdd [3:0:0:22] disk IET VIRTUAL-DISK 0 /dev/sde [3:0:0:23] disk IET VIRTUAL-DISK 0 /dev/sdf [3:0:0:24] disk IET VIRTUAL-DISK 0 /dev/sdg [3:0:0:25] disk IET VIRTUAL-DISK 0 /dev/sdh [3:0:0:26] disk IET VIRTUAL-DISK 0 /dev/sdi [3:0:0:27] disk IET VIRTUAL-DISK 0 /dev/sdj [3:0:0:28] disk IET VIRTUAL-DISK 0 /dev/sdk [3:0:0:29] disk IET VIRTUAL-DISK 0 /dev/sdl [3:0:0:30] disk IET VIRTUAL-DISK 0 /dev/sdm [3:0:0:31] disk IET VIRTUAL-DISK 0 /dev/sdn [3:0:0:32] disk IET VIRTUAL-DISK 0 /dev/sdo [3:0:0:33] disk IET VIRTUAL-DISK 0 /dev/sdp [3:0:0:34] disk IET VIRTUAL-DISK 0 /dev/sdt [3:0:0:35] disk IET VIRTUAL-DISK 0 /dev/sdu [3:0:0:36] disk IET VIRTUAL-DISK 0 /dev/sdv [3:0:0:37] disk IET VIRTUAL-DISK 0 /dev/sdw [3:0:0:38] disk IET VIRTUAL-DISK 0 /dev/sdx [3:0:0:39] disk IET VIRTUAL-DISK 0 /dev/sdy [3:0:0:40] disk IET VIRTUAL-DISK 0 /dev/sdz [3:0:0:41] disk IET VIRTUAL-DISK 0 /dev/sdq [3:0:0:42] disk IET VIRTUAL-DISK 0 /dev/sdr [3:0:0:43] disk IET VIRTUAL-DISK 0 /dev/sdai [3:0:0:44] disk IET VIRTUAL-DISK 0 /dev/sdaa [3:0:0:45] disk IET VIRTUAL-DISK 0 /dev/sdae [3:0:0:46] disk IET VIRTUAL-DISK 0 /dev/sdab [3:0:0:47] disk IET VIRTUAL-DISK 0 /dev/sdaf [3:0:0:48] disk IET VIRTUAL-DISK 0 /dev/sdad [3:0:0:49] disk IET VIRTUAL-DISK 0 /dev/sdag [3:0:0:50] disk IET VIRTUAL-DISK 0 /dev/sdac [3:0:0:51] disk IET VIRTUAL-DISK 0 /dev/sdah [3:0:0:52] disk IET VIRTUAL-DISK 0 /dev/sdaj [3:0:0:53] disk IET VIRTUAL-DISK 0 /dev/sdak [3:0:0:54] disk IET VIRTUAL-DISK 0 /dev/sdal [3:0:0:55] disk IET VIRTUAL-DISK 0 /dev/sdam [7:0:0:0] disk LIO-ORG IBLOCK 4.0 /dev/sdan [7:0:0:1] disk LIO-ORG IBLOCK 4.0 /dev/sdao -- Per Jessen, Zürich (3.4°C) http://www.dns24.ch/ - free dynamic DNS, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

Op donderdag 3 maart 2016 09:59:52 CET schreef Greg Freemyer:

On Thu, Mar 3, 2016 at 9:40 AM, Per Jessen wrote:

...

Ken Schneider wrote:

...

On 03/03/2016 08:51 AM, Per Jessen wrote:

...

I've been playing with an Intel Compute Stick which has just one USB port. I've attached a cheap USB-hub to add another 3 ports - one for a USB harddrive, one for the wireless keyboard+mouse and one for a wifi dongle. I tried building a kernel (/usr/src/linux on the usb harddrive) with make -j4, but this led almost immediately to a crash/disconnect/io-errors, so I scaled back to make -j1.

I was wondering if I should be worried about the technnical quality of the USB hub?

Absolutely. Make sure the hub you are using supplies its own power or you will have problems with any device that needs more then a little power.

The USB harddrive has its own supply, and the two dongles can't be drawing that much. I was more thinking about dodgy hardware that doesn't do well with concurrent requests? Still, good point about the power, thanks.

Per,

I'm the heavy external drive connected via USB hub user on the list.

Anker brand USB 3 hubs are the only ones I trust. I've bought and discarded 2 other brands.

fyi: My 64GB lab machine currently has about 20 external USB drives hooked up to it. It's been that way for over a week. With the non-Anker hubs I would see USB connection disconnects/re-connects at least once every 24 hours, so I couldn't maintain a long term mount like this.

fyi2: I've never gone past /dev/sdz (ie. the 26th drive in a system) but I'm now close enough to think about it. What comes after /dev/sdz?

Greg

/dev/sdaa, see https://lists.debian.org/debian-isp/2010/12/msg00025.html -- Gertjan Lettink, a.k.a. Knurpht openSUSE Board Member openSUSE Forums Team -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

03.03.2016 20:06, Greg Freemyer пишет:

Hopefully I will never learn first hand that /dev/sdzz is followed by /dev/sdaaa

Well, 4 paths to LUN is pretty common with enterprise SAN storage (2 x host HBAs to 2 storage controllers, each HBA sees both controllers), so it takes "just" 170 LUNs to exceed two letters namespace ... -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

On Thu, Mar 3, 2016 at 12:35 PM, Per Jessen wrote:

Andrei Borzenkov wrote:

...

03.03.2016 20:06, Greg Freemyer пишет:

...

Hopefully I will never learn first hand that /dev/sdzz is followed by /dev/sdaaa

Well, 4 paths to LUN is pretty common with enterprise SAN storage (2 x host HBAs to 2 storage controllers, each HBA sees both controllers), so it takes "just" 170 LUNs to exceed two letters namespace ...

I was about to say something similar - we carve out LVs for virtual machines, and hand those out via iSCSI. Exceeding 26*26 = 676 is not that far away.

Masochist -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

Per Jessen wrote:

Greg Freemyer wrote:

...

On Thu, Mar 3, 2016 at 12:35 PM, Per Jessen wrote:

...

Andrei Borzenkov wrote:

...

03.03.2016 20:06, Greg Freemyer пишет:

...

Hopefully I will never learn first hand that /dev/sdzz is followed by /dev/sdaaa

Well, 4 paths to LUN is pretty common with enterprise SAN storage (2 x host HBAs to 2 storage controllers, each HBA sees both controllers), so it takes "just" 170 LUNs to exceed two letters namespace ...

I was about to say something similar - we carve out LVs for virtual machines, and hand those out via iSCSI. Exceeding 26*26 = 676 is not that far away.

Masochist

Top points! for being on-topic, Greg - I almost spilled my beer :-)

TBH, actual device names are rarely used for anything. On the xen host, it's more like this: /dev/mapper/srv002181r - root /dev/mapper/srv002181u - user /dev/mapper/srv002181s - swap It's only with 'lsscsi' that the display becomes really impressive :-) -- Per Jessen, Zürich (2.5°C) http://www.dns24.ch/ - your free DNS host, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org

On 03/03/2016 09:06 AM, Greg Freemyer wrote:

...

...

fyi2: I've never gone past /dev/sdz (ie. the 26th drive in a system)

...

...

but I'm now close enough to think about it. What comes after /dev/sdz?

Greg

/dev/sdaa, seehttps://lists.debian.org/debian-isp/2010/12/msg00025.html

Hopefully I will never learn first hand that /dev/sdzz is followed by /dev/sdaaa

I've got one system that has 220 disks (don't ask). While many of them are RAID'ed, I've had as many as 96 as JBOD's. I believe I got down to /dev/sddx at one point. I always wondered how a Windows server would handle all those disks... Regards, Lew -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org