[patch] Re: SU+J on 9.1-RC2 ISO

[Bas Smeelen]

On 11/02/2012 07:59 PM, Gary Palmer wrote:
> On Fri, Nov 02, 2012 at 07:41:31PM +0100, Mateusz Guzik wrote:
>> On Fri, Nov 02, 2012 at 07:30:04PM +0100, Bas Smeelen wrote:
>>> On 11/02/2012 07:17 PM, Bas Smeelen wrote:
>>>> On 11/02/2012 07:08 PM, Bas Smeelen wrote:
>>>>> On 11/02/2012 06:27 PM, Adam Strohl wrote:
>>>>>> On 11/3/2012 0:13, Mike Jakubik wrote:
>>>>>>> You can disable SU+J after installing, though it would be nice if the
>>>>>>> installer gave you a choice.
>>>>>> This assumes that you know about this flaw, which most people do not.
>>>>>>
>>>>>> I didn't until I discovered it by panic-ing a perfectly fine running
>>>>>> server.  Getting burned by a known bug like this shouldn't be "SOP"
>>>>>> for users of FreeBSD.
>>>>>>
>>>>>> If anything it should be turned off by default, and people can turn it
>>>>>> on if they want given the landmine it plants.  If they know how to
>>>>>> turn it on they're much more likely to be aware of the issue.
>>>>>>
>>>>>>
>>>>>>
>>> To sum it up
>>> SU+J should be turned off by default because of
>>> 1. It does not work with dumping a live system e.g. snapshot
>>> 2. it is not recommended for SSD installs
>>> 3. "Smart" admins can turn it on if they want
>>>
>>> root at sys:/usr/src/usr.sbin/bsdinstall/partedit # diff -u gpart_ops.c
>>> gpart_ops.cnew
>>> --- gpart_ops.c    2012-08-06 01:54:33.000000000 +0200
>>> +++ gpart_ops.cnew    2012-11-02 19:07:45.000000000 +0100
>>> @@ -90,8 +90,8 @@
>>>                {"SU", "Softupdates",
>>>                    "Enable softupdates (default)", 1 },
>>>                {"SUJ", "Softupdates journaling",
>>> -                "Enable file system journaling (default - "
>>> -                "turn off for SSDs)", 1 },
>>> +                "Disable file system journaling (default - "
>>> +                "turn on for adventurish admins)", 0 },
>>>                {"TRIM", "Enable SSD TRIM support",
>>>                    "Enable TRIM support, useful on solid-state drives",
>>>                    0 },
>>>
>>> Please comment, then I can file a PR or not
>> As was noted in my another mail, the kernel will no longer crash when an
>> attempt to take a snapshot is made. Also AFAIR SUJ can be disabled
>> later.
>>
>> Given that I prefer the following:
>>
>> diff --git a/usr.sbin/bsdinstall/partedit/gpart_ops.c b/usr.sbin/bsdinstall/partedit/gpart_ops.c
>> index 479365a..80296c2 100644
>> --- a/usr.sbin/bsdinstall/partedit/gpart_ops.c
>> +++ b/usr.sbin/bsdinstall/partedit/gpart_ops.c
>> @@ -91,7 +91,7 @@ newfs_command(const char *fstype, char *command, int use_default)
>>   			    "Enable softupdates (default)", 1 },
>>   			{"SUJ", "Softupdates journaling",
>>   			    "Enable file system journaling (default - "
>> -			    "turn off for SSDs)", 1 },
>> +			    "turn off for SSDs or if you use snapshots)", 1 },
>>   			{"TRIM", "Enable SSD TRIM support",
>>   			    "Enable TRIM support, useful on solid-state drives",
>>   			    0 },
>>
>> http://people.freebsd.org/~mjg/patches/suj-snapshot-comment.diff
> How many people realise that snapshots are needed for dump based backups
> (and other related features)?
>
> Gary

My guess? A lot.
But most who realize would turn SU+J off on new installs.
I just ran across this when doing a new install from 9.1-RC2 and not 
paying attention e.g. realizing that SU+J is turned on by default now.
I have seen coming this across the mail lists before though.



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