# IO error at virtual disk **URL:** \ **Category:** SLES Hardware\ **Created:** [October 8, 2018, 3:08pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019 "2018-10-08T15:08:08Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![sharfuddin](https://avatars.discourse-cdn.com/v4/letter/s/e274bd/32.png) [@sharfuddin](https://forums.suse.com/u/sharfuddin)\ **Post date:** [October 8, 2018, 3:08pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019/1 "2018-10-08T15:08:08Z")
Its a VM(SLES 12 SP2) running on ESX 6.5. ESX is not showing any error, while at OS we are getting following errors: kernel: [787030.198763] end\_request: I/O error, dev sda, sector 3759139416 kernel: [1530802.448197] end\_request: I/O error, dev sda, sector 3754016448 kernel: [1912330.306074] end\_request: I/O error, dev sda, sector 3719306720 kernel: [1954566.577314] end\_request: I/O error, dev sda, sector 3722956392 The disk(sda) is a virtual disk. Please help, what and where should I check ? ---
**Author:** ![Jens-U](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@Jens-U](https://forums.suse.com/u/Jens-U)\ **Post date:** [October 8, 2018, 3:35pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019/2 "2018-10-08T15:35:08Z")
Hi sharfuddin, > kernel: [787030.198763] end\_request: I/O error, dev sda, sector 3759139416 > Please help, what and where should I check ? are those reported sector numbers within the virtual disk’s size? If not, those errors could be the result of a on-disk corruption (invalid sector numbers/offsets stored in whatever you put on that disk). Everything else depends on how that virtual disk is provisioned… is it from some VMFS pool? SAN? If it’s some back-end storage system, does it report any errors? Regards, J ---
**Author:** ![sharfuddin](https://avatars.discourse-cdn.com/v4/letter/s/e274bd/32.png) [@sharfuddin](https://forums.suse.com/u/sharfuddin)\ **Post date:** [October 8, 2018, 9:04pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019/3 "2018-10-08T21:04:24Z")
[QUOTE=jmozdzen;54722]Hi sharfuddin, > kernel: [787030.198763] end\_request: I/O error, dev sda, sector 3759139416 > Please help, what and where should I check ? are those reported sector numbers within the virtual disk’s size? If not, those errors could be the result of a on-disk corruption (invalid sector numbers/offsets stored in whatever you put on that disk). Everything else depends on how that virtual disk is provisioned… is it from some VMFS pool? SAN? If it’s some back-end storage system, does it report any errors? Regards, J[/QUOTE] > are those reported sector numbers within the virtual disk’s size? How can I find this… via “fdisk -l” ? Actually don’t have access to the system right now. > is it from some VMFS pool? > Yes. > SAN? > No, locally attached disk on ESX host ---
**Author:** ![Jens-U](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@Jens-U](https://forums.suse.com/u/Jens-U)\ **Post date:** [October 9, 2018, 12:54pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019/4 "2018-10-09T12:54:30Z")
Hi sharfuddin, [QUOTE=sharfuddin;54724]\>are those reported sector numbers within the virtual disk’s size? > How can I find this.. via “fdisk -l” ? Actually don’t have access to the system right now. [/QUOTE] yes, can be a good information source. Have a look at the start and end sector information for your partitions. [QUOTE=sharfuddin;54724]\>SAN? No, locally attached disk on ESX host[/QUOTE] You wrote that ESX had nothing in the logs - did you also look at ESX-system-related logs or just at those directly related to your virtual machine? If the latter, a look at the system logs might reveal information about intermittent disk errors reported by the system. Also, while I do not trust SMART further than I can throw our servers, maybe some SMART pre-failure error indicators may have increased. For below to work, you’ll of course need to know which disks are actually used - or if it’s hardware RAID, will have to take a totally different approach. Speaking of (hardware or software) RAID: If it’s in use, do you give your arrays a check run at least once a week? The older the disks, the more important this can get to detect silently introduced consistency errors (this is, of course, completely unrelated to ESX, but a generally applicable advice). [CODE]# esxcli storage core device list # esxcli storage core device smart get -d device[/CODE] Regards, J ---
**Author:** ![KEVIN1](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KEVIN1](https://forums.suse.com/u/KEVIN1)\ **Post date:** [October 9, 2018, 10:06pm UTC](https://forums.suse.com/t/io-error-at-virtual-disk/33019/5 "2018-10-09T22:06:38Z")
sharfuddin wrote: [color=blue] > Its a VM(SLES 12 SP2) running on ESX 6.5. ESX is not showing any > error, while at OS we are getting following errors: > > kernel: [787030.198763] end\_request: I/O error, dev sda, sector > 3759139416 > kernel: [1530802.448197] end\_request: I/O error, dev sda, sector > 3754016448 > kernel: [1912330.306074] end\_request: I/O error, dev sda, sector > 3719306720 > kernel: [1954566.577314] end\_request: I/O error, dev sda, sector > 3722956392 > > The disk(sda) is a virtual disk. > > Please help, what and where should I check ?[/color] If SLES is reporting these errors, I would do a filesystem check from within SLES and see what it reports. – Kevin Boyle - Knowledge Partner If you find this post helpful and are logged into the web interface, please show your appreciation and click on the star below this post. Thank you.